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A Phylogenetic Analysis of Dicoma Cass. and Related Genera (Asteraceae: Cichorioideae: Mutisieae) Based on Morphological and Anatomic Characters
Abstract
This study reports a phylogenetic analysis of the genus Dicoma and the related genera Achyrothalamus, Erythrocephalum, Pasaccardoa, and Pleiotaxis (Mutisieae, Asteraceae), which share a series of morphological characters of the corolla, ray floret epidermis, anther appendages, and style branches. A matrix of 77 morphological and anatomical characters was used for the analysis. The genera Gochnatia and Oldenburgia were used as outgroups. The topology of the resulting consensus cladogram suggests that the genus Dicoma appears paraphyletic. A clade including Dicoma and Pasaccardoa appears monophyletic with subgroups clearly defined by a large number of synapomorphies. These findings indicate that maintenance of Pasaccardoa as an independent genus implies a need to divide Dicoma into several genera. The genera Pleiotaxis, Achyrothalamus, and Erythrocephalum form a monophyletic group. Issues relating to the geographical origin of Dicoma (probably Madagasear or southern Africa), and to the evolution of the different species groups, are briefly discussed.
... According to his study, however, the species of the Dicoma group are characterized by a corolla distinctly divided into a narrow tube and wide limb, a non-mutisioid ray floret epidermial pattern, acuminate apical anther appendages, and mostly subapically pilose style branches. This group of genera was studied in a morphological phylogenetic analysis by Ortiz (2000), who concluded that the two genera, Pleiotaxis and Erythrocephalum Benth., formed a monophyletic group and that the genus Dicoma was paraphyletic and should be split into several genera. Kim et al. (2002), in their phylogenetic analysis of the tribe Mutisieae based on sequencing of the chloroplast DNA marker ndhF, concluded that some African Mutisieae are more related to Cardueae than to Mutisieae s.str. ...
... The topology of the trees supports the split of Dicoma into three genera (Dicoma s.str., Macledium, and Cloiselia), as was proposed by Ortiz (2000) in his morphological phylogenetic analysis. Figure 17.4 shows the relationships among the various groups now accepted as three (and possibly four) different genera (Ortiz 2000(Ortiz , 2001(Ortiz , 2006 Marginal florets white to red, bilabiate, with the inner lips coiled or not, or ray; disc florets actinomorphic or rarely zygomorphic, deeply 5-lobed; corolla white, yellow, cream to pink or mauve, glabrous to pubescent with different types of glandular, or rarely eglandular, hairs; anthers 5, caudate and calcarate, rarely ecalcarate, with long tapering or subobtuse tails, ramified, with often acute branches, rarely obtuse, these being retrorse along the tail and lacking or antrorse at the apex, apical appendage acute to acuminate, endothecial tissue polarized, pollen smooth to echinate; style short or long bifid, with Part of the strict consensus tree of three equally most parsimonious cladograms, based on analysis of ITS (rDNA) sequences (Ortiz et al., unpub.). ...
... The topology of the trees supports the split of Dicoma into three genera (Dicoma s.str., Macledium, and Cloiselia), as was proposed by Ortiz (2000) in his morphological phylogenetic analysis. Figure 17.4 shows the relationships among the various groups now accepted as three (and possibly four) different genera (Ortiz 2000(Ortiz , 2001(Ortiz , 2006 Marginal florets white to red, bilabiate, with the inner lips coiled or not, or ray; disc florets actinomorphic or rarely zygomorphic, deeply 5-lobed; corolla white, yellow, cream to pink or mauve, glabrous to pubescent with different types of glandular, or rarely eglandular, hairs; anthers 5, caudate and calcarate, rarely ecalcarate, with long tapering or subobtuse tails, ramified, with often acute branches, rarely obtuse, these being retrorse along the tail and lacking or antrorse at the apex, apical appendage acute to acuminate, endothecial tissue polarized, pollen smooth to echinate; style short or long bifid, with Part of the strict consensus tree of three equally most parsimonious cladograms, based on analysis of ITS (rDNA) sequences (Ortiz et al., unpub.). Three genera of Barnadesieae and a broad selection of taxa from Mutisieae s.l. were used as outgroups. ...
... In a previous publication (Ortiz, 2000), continuing our studies of Dicoma and related genera (Ortiz & Rodriguez-Oubifia, 1994, 1996Rodriguez-Oubifia & Ortiz, 1997;Ortiz & al., 1998), I have completed a detailed study of the Dicoma group sensu Bremer, confirming the paraphyletic nature of Dicoma. In this article we focus on the anatomical and morphological differences between one of the groups of species identified in this phylogenetic analysis (Ortiz, 2000) and Dicoma s.str. ...
... In a previous publication (Ortiz, 2000), continuing our studies of Dicoma and related genera (Ortiz & Rodriguez-Oubifia, 1994, 1996Rodriguez-Oubifia & Ortiz, 1997;Ortiz & al., 1998), I have completed a detailed study of the Dicoma group sensu Bremer, confirming the paraphyletic nature of Dicoma. In this article we focus on the anatomical and morphological differences between one of the groups of species identified in this phylogenetic analysis (Ortiz, 2000) and Dicoma s.str. ...
... Also examined are species related to the "D. sessiliflora group" (Table 1) not included in the analysis of Ortiz (2000). For microscopic examination of floral parts, these were first boiled in water with a surfactant, and then mounted in Hoyer's solution (Anderson, 1954). ...
Ortiz, S.: Reinstatement of the genus Macledium Cass. (Asteraceae, Mutisieae): morphological and phylogenetic arguments. ‐ Taxon 50: 733–744. 2001. ‐ISSN 0040‐0262.
Studies of the genus Dicoma Cass. (Asteraceae , tribe Mutisieae) indicate that this taxon as currently defined is paraphyletic, and in fact comprises three groups showing marked morphological and anatomical differences. One of these groups is differentiated from Dicoma s.str. by a large number of characters relating to morphology and anatomy of phyllaries, corolla, anthers, style, cypsela, and testa. It is proposed that these species should be considered as a separate genus, for which the name Macledium Cass. has nomenclatural priority. A brief nomenclatural synopsis is presented, including synonyms and nomenclatural types for each taxon in this genus of 20 species.
... -The well-supported Dicomeae clade (BP = 96, PP = 1.00) is divided into two subclades, one of which is maximally supported and comprises Pleiotaxis and Erythrocephalum (BP = 100, PP = 1.00), while the other, Pasaccardoa + Dicoma s.l., is less clear (BP = 56, PP = 0.83). This same topology was obtained by Ortiz (2000) using 77 morphological characters, and its two subclades were also found by Ortiz & al. (2009b), although in this last study they did not form a monophyletic group. In view of these results and relevant palynological data (Coutinho & al., 2012), and in spite of the limited support for the second subclade in the present study, we propose that these two subclades should be recognized as subtribes within Dicomeae. ...
... Cyn. In the morphological analysis of Ortiz (2000), Erythrocephalum was also monophyletic, but Pleiotaxis was paraphyletic. The relationships within Pleiotaxis in Figs. 1 and 2 are very interesting: seven species with broad, campanulate, red-to-purple-floreted capitula that are solitary or arranged in loose corymbiform inflorescences form a monophyletic group that forms a polytomy with two monospecific clades, P. subpaniculata Chiov. ...
... The Dicominae clade. -The topology of this clade corroborates the morphological phylogenetic analysis of Ortiz (2000), except that the first branch is now Macledium instead of Cloiselia. Both these genera-traditionally included in Dicoma (Hoffmann, 1890(Hoffmann, , 1893Wilson, 1923;Jeffrey, 1967;Cabrera, 1977;Hansen, 1991;Pope, 1991;Bremer, 1994) but recently reinstated by Ortiz (2000Ortiz ( , 2001Ortiz ( , 2006-are monophyletic, while Dicoma s.l. is polyphyletic. ...
A molecular phylogenetic study of the African Mutisieae s.l. (Asteraceae) was performed using the chloroplast markers ndhF and trnL-F. The sequences of 46 species, including three representatives of Cynareae (Cardueae), were analysed applying maximum parsimony and Bayesian inference, with Mutisia and Hecastocleis as outgroups. Four main clades corresponding to the tribes Cynareae, Dicomeae, Tarchonantheae and Oldenburgieae were identified, although relationships among them were unresolved. Dicomeae split into two main clades, which on the basis of these results and a previous morphological-anatomical phylogenetic analysis are proposed as two new subtribes: Dicominae and Pleiotaxinae. Within Dicominae, Dicoma welwitschii is located outside the Dicoma clade, in a clade that includes the Pasaccardoa species. Given the singular morphology of D. welwitschii, the new genus Dicomopsis has been proposed. A more detailed study with additional markers will be necessary to decide whether Pasaccardoa baumii should be included in Dicomopsis or described as a monotypic genus. The topology of the Tarchonantheae clade does not contribute to elucidating the relationships between Tarchonanthus and Brachylaena. The four species of Oldenburgia form a well-supported monophyletic group (Oldenburgieae), despite their heterogeneous morphology.
... More recently, a cladistic analysis of Dicoma and related genera based on morphological data ( Fig. 1) concluded that Dicoma carbonaria and D. oleifolia constitute a monophyletic group supported by numerous synapomorphies (Ortiz 2000; Table 1). By contrast, Dicoma as traditionally defined is paraphyletic, becoming monophyletic only if the species of the genus Pasaccardoa Kuntze are included. ...
... In line with these results and bearing in mind the marked morphological differences between the components of the different clades mak-ing up the Dicoma ϩ Pasaccardoa group (Table 1), I proposed the separation of this group into monophyletic genera. In a previous publication (Ortiz 2001), I proposed reinstatement of the genus Macledium Cass., and transfered to this genus 20 species previously included in Dicoma. Continuing in the same line, I here propose the reinstatement of the genus Cloiselia, and present a detailed systematic review of this genus. ...
... Funk et al. (2005) placed Cloiselia carbonaria within a clade also including Macledium, Pasaccardoa, and Dicoma, forming part of the new tribe Dicomeae proposed by these authors (Panero and Funk 2002); the seven genera making up this new tribe include most of the African genera previously included in the tribe Mutisieae. These authors' consideration of Cloiselia ϩ Macledium ϩ Pasaccardoa ϩ Dicoma as a monophyletic clade is in line with my conclusions (Ortiz 2000) noted above. Panero and Funk additionally suggest that Dicomeae and the tribes Tarchonantheae and Carduae together constitute the subfamily Carduoideae. ...
Studies of the genus Dicoma (Asteraceae, tribe Mutisieae s. 1.) indicate that this taxon as currently defined is paraphyletic, and in fact comprises at least three groups showing marked morphological and anatomical differences. One of these groups is differentiated from Dicoma s. str. by a large number of characters relating to the morphology and anatomy of the phyllaries, corolla, anthers, style, cypsela, and testa. This paper proposes that this group should be considered as a separate genus, for which the name Cloiselia S. Moore has nomenclatural priority. The article presents a systematic study of Cloiselia, which comprises four species: two are new (C. madagascariensis and C. humbertii) and one is a new combination (C. oleifolia).
... The genus Dicoma Cass. of the tribe Dicomeae of the family Compositae (Asteraceae) comprises in its wide circumscription about 50 species of herbs, shrubs or, rarely, small trees, mainly distributed in tropical and southern Africa and Madagascar (Ortiz et al. 1998). A phylogenetic analysis of Dicoma based on morphological and anatomical characters by Ortiz (2000Ortiz ( , 2001 revealed the necessity to reconsider the delimitation of the genus. Facing the choice of either enlarging Dicoma to include also the small tropical African genus Pasaccardoa Kuntze, or to split it into three smaller genera, Ortiz (2000Ortiz ( , 2001 provided convincing arguments for the latter alternative and reinstated Macledium Cass. ...
... A phylogenetic analysis of Dicoma based on morphological and anatomical characters by Ortiz (2000Ortiz ( , 2001 revealed the necessity to reconsider the delimitation of the genus. Facing the choice of either enlarging Dicoma to include also the small tropical African genus Pasaccardoa Kuntze, or to split it into three smaller genera, Ortiz (2000Ortiz ( , 2001 provided convincing arguments for the latter alternative and reinstated Macledium Cass. with about 20 species of tropical and southern Africa (Ortiz 2001) and Cloiselia S. Moore with four shrubby and tree-like species of Madagascar (Ortiz 2006). ...
... Dicoma chatanensis clearly belongs to Dicoma s.s. (Ortiz 2000(Ortiz , 2001, because of, in particular, (1) the corolla without long twin glandular hairs, (2) corolla lobes rolled backwards spirally at anthesis, (3) the anther tails distally with acute retrorse ramifications (Ortiz 2000, his Fig. 5, in the caption erroneously termed 'antrorse'), (4) the ribbed achenes with trichomes situated between the ribs, (5) the involucral bracts with a conspicuous midvein and longitudinal herbaceous stripes on either side. The species shows morphological affinities to a group of three mesic species, especially to Dicoma aethiopica S. Ortiz & Rodr. ...
Three species of Dicoma and one of the newly re-established segregate genus Macledium (Dicomeae) are recognized on the Arabian Peninsula and Socotra. The (sub)shrubby Dicoma chatanensis N. Kilian sp. nov. with affinities especially to D. aethiopica from southwest Ethiopia, is described from open habitats of the sea-facing escarpments of Jabal Chatan in east Al-Mahra, Yemen. Based on additional material, D. schimperi subsp. cinerea is reconsidered to have a disjunct distribution in north Somalia and southeast Yemen, in the latter region replacing subsp. schimperi. Dicoma tomentosa is very rare in the area and known only from southwest Saudi Arabia, north Yemen and, as a rare weed, from Socotra. The common description and illustration (under Dicoma) of the flowers of the Socotran endemic Macledium canum with lobes rolled backwards spirally is confirmed to be erroneous and a lectotype is designated for the basionym. A key to the four species is provided.
... Oubiña described from Tanzania, shows all the usual characteristics of the genus but with obtuse and entire phyllaries (Ortiz & Rodríguez-Oubiña, 1998). Furthermore, previous morphological phylogenetic analysis (Ortiz, 2000) provides clear evidence that A. marginatus O.Hoffm., the sole species of that genus, belongs in Erythrocephalum. In accordance with subsequent molecular findings (Ortiz & al., 2013), these two genera form a monophyletic group; however, that analysis only included two species and it is not possible to determine whether Achyrothalamus marginatus should be placed within Erythrocephalum or it should be treated as a sister group. ...
An alphabetical list of all the validly published names of taxa in Erythrocephalum (Asteraceae: Dicomeae) is presented with details of all types of which four are new lectotypifications and three new neotypifications. The names first published in Achyrothalamus and Haemastegia are also included. All names are assigned to their accepted taxa in this synopsis, the first published for the genus, which also includes an analytical key and information on distribution. © 2018, International Association for Plant Taxonomy. All rights reserved.
... The genus Dicoma Cass. (Asteraceae) comprises approximately 35 species, 16 of which are confined to southern Africa (Ortiz, 2001). Seven species are recorded for Zimbabwe (Wild, 1972). ...
The study aimed at evaluating the phytochemical profile and anti-nociception activity of root crude extracts of D. niccolifera, a plant commonly used to alleviate painful conditions by local communities. Standard phytochemical screening tests revealed presence of tannins, alkaloids, flavonoids, terpenoids, reducing sugars, cardiac glycosides and anthraquinones. Anti-nociception was assessed using the hot plate model on Swiss Albino mice. Mice intraperitoneally injected with root crude extract showed that the D. niccolifera root extract had analgesic activity by taking longer to react to the thermal stimulus than the control group. The extract higher doses of 500 and 1000mg/kg showed peak mean latency times of 2.39 and 2.12 seconds respectively. These latency times were found to be significantly different (p<0.05) from the control. The anti-nociception activity may be attributed to the phenolic compounds in the extract. The study validates the use of D. niccolifera in managing painful conditions.
... The current tribal position of Pleiotaxis is controversial. Some authors regard Pleiotaxis as forming part of a mutisiean ''Dicomagroup'' (Bremer, 1994;Ortiz, 2000;Ortiz & Coutinho, 2001). According to Hansen (1991), this group of genera (including Pleiotaxis) should be excluded from Mutisieae by features of style branches, anthers, and pollen type. ...
Gochnatia is one of the largest genera of the tribe Mutisieae (Asteraceae) and has been traditionally characterized by its homogamous capitula with isomorphic corollas. A morphological study of Gochnatia and associated genera, i.e., Actinoseris, Chucoa, Cnicothamnus, Cyclolepis, Hyalis, Ianthopappus, Nouelia, Pleiotaxis, and Wunderlichia, was carried out to evaluate the circumscription of Gochnatia and its sections, and the affinities of this complex of genera. The characters studied involve habit, leaf features (consistency, pubescence type, shape, margin, and venation), types of capitulescenee, involucre features (shape, size, phyllary series, pubescence, and shape), paleae, floret features (morphology, sex, number, color of corolla, anthers, style shapes, achenial pubescence, and pappus). Analysis of these features revealed: (1) although Gochnatia is highly variable in most of the characters studied, it can be defined by this suite of features: isomorphic to subdimorphic corollas, apiculate anther appendages, and smooth style branches; (2) sections of Gochnatia needed to be re-evaluated. As result of this, two sections, i.e., sect. Discoseris and sect. Pentaphorus, are confirmed; two sections are proposed, i.e., sect. Glomerata sect. nov. and sect. Rotundifolia sect. nov.; three sections are redefined, i.e., sect. Hedraiophyllum, sect. Leucomeris, and sect. Gochnatia, while sect. Anastraphioides is formally published; and (3) the combination of apiculate anther appendages and smooth style branches is unique to Actinoseris, Cnicothamnus, Cyclolepis, Gochnatia, Hyalis, Ianthopappus, and Nouelia within the Mutisieae. This group of genera is recognized here as the Gochnatia complex, with Gochnatia as the basal genus of this complex. Chucoa, Pleiotaxis, and Wunderlichia do not belong to the Gochnatia complex.
... Therefore, resolution of relationships within the Mutisieae is fundamental for understanding the systematics and evolution of the family. Some attempts were made to delimit generic groups (e.g., Jeffrey 1967;Hansen 1990;Bremer 1994;Ortiz 2000;Freire et al. 2002;Panero and Funk 2002) as a first step to solve the taxonomy of the tribe. Whereas some genera were clearly and easily grouped according to their shared characters, others such as Chaetanthera have been more difficult to fit. ...
... Bremer (1994) followed conclusions from cladistic studies by Karis et al. (1992) that Dicoma , Erythrocephalum, and Pleiotaxis were members of Mutisieae, and he maintained the genera as such under the informal Dicoma group. Cladistic studies of the Dicoma group by Ortiz (2000) using Oldenburgia and Gochnatia as outgroups, showed Erythrocephalum and Pleiotaxis to be sister to a paraphyletic Dicoma with the species of Pasaccardoa derived from within it. Subsequent studies by Ortiz (2001 Ortiz ( , 2006) refined the concept of Dicoma and the Dicoma group to contain also Cloiselia, Dicoma, Erythrocephalum, Gladiopappus, Macledium, Pleiotaxis, and Pasaccardoa. ...
... We are currently carrying out a monographic study of Dicoma (Ortiz & Rodríguez-Oubiña, 1994, 1996Ortiz, Rodríguez-Oubiña & Tadesse, 1998;Ortiz, 2000;Ortiz & Pulgar, 2000;Ortiz & Coutinho, 2001, etc.) and related genera of the Mutisieae from tropical and southern Africa. In the course of this work we have found in the material collected by Dinter in Namibia a new species that we describe herein. ...
During studies of the genus Dicoma (Asteraceae: Mutisieae), and specifically of the material collected by Dinter in Namibia, we have found a new species named Dicoma obconica. This species has previously been misinterpreted as D. picta (Thunb.) Druce. We present a description with illustrations, and discuss relationships with D. picta and with D. dinteri S. Moore, the most similar species of the genus. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 139, 317–322.
... Bremer (1994) followed conclusions from cladistic studies by Karis et al. (1992) that Dicoma , Erythrocephalum, and Pleiotaxis were members of Mutisieae, and he maintained the genera as such under the informal Dicoma group. Cladistic studies of the Dicoma group by Ortiz (2000) using Oldenburgia and Gochnatia as outgroups, showed Erythrocephalum and Pleiotaxis to be sister to a paraphyletic Dicoma with the species of Pasaccardoa derived from within it. Subsequent studies by Ortiz (2001 Ortiz ( , 2006) refined the concept of Dicoma and the Dicoma group to contain also Cloiselia, Dicoma, Erythrocephalum, Gladiopappus, Macledium, Pleiotaxis, and Pasaccardoa. ...
... Nevertheless, the existence of a continuous transition among the quantitative pollen characters of the Dicominae species we examined (Table 1) did not enable us to define two pollen types for this subtribe. On the contrary, we consider that our results support the existence of a large clade comprising the Macledium, Pasaccardoa, ''Dicomopsis'', Dicoma, and Cloiselia clades (Ortiz 2000; Ortiz et al. 2009), because the pollen grains of all these genera share important features, namely thick, more or less straight, dense supporting columellae , lalongate mesoapertures, and perforate (rarely rugulate-perforate) inter-spinular sculpture. The average values we found for the equatorial diameter (46.00 lm), the exine thickness (7.50 lm), and the ratio ''E/exine thickness'' (6.13) of the Dicomeae are quite close to those indicated by Bolick (1991) for both the MutisieaeTable 3 Pollen quantitative characteristics of some tribes related to the Dicomeae Tribe Pollen morphology in tribe Dicomeae 1861 (respectively: 43.10, 6.50, and 6.60 lm) and Cardueae (respectively: 49.10, 6.50, and 7.50 lm). ...
To better understand the taxonomy and phylogeny of the Dicomeae (Asteraceae) the pollen morphology of seven genera including 15 species of that tribe and six genera with seven species belonging to five related tribes was studied by use of light and scanning electron microscopy. The quantitative data were analysed by use of principal-components analysis (PCA). The exine ultrastructure of Erythrocephalum longifolium and Pleiotaxis rugosa was also studied by use of transmission electron microscopy. Three pollen types were distinguishable from the apertural, columellar, and spinular morphology and inter-spinular sculpture. A dichotomous key to these pollen types is proposed. The existence of the Dicomeae as an independent tribe and its subdivision in two subtribes (Dicominae and Pleiotaxinae) are supported by this study, which also suggests the Oldenburgieae and the Tarchonantheae are the closest tribes to Dicomeae.
... Therefore, resolution of relationships within the Mutisieae is fundamental for understanding the systematics and evolution of the family. Some attempts were made to delimit generic groups (e.g., Jeffrey 1967;Hansen 1990;Bremer 1994;Ortiz 2000;Freire et al. 2002;Panero and Funk 2002) as a first step to solve the taxonomy of the tribe. Whereas some genera were clearly and easily grouped according to their shared characters, others such as Chaetanthera have been more difficult to fit. ...
Chaetanthera is a South American genus of 43 species in seven subgenera. Pollen grain morphology of 39 species of Chaetanthera and allied genera of Mutisiinae was surveyed using light and electron microscopy. Two palynologic groups are distinguished in Chaetanthera, defined as types I and II, the latter with the subtypes II 1 and II 2. The groups are supported by additional morphological and habit characteristics. Type I has pollen with a thinner exine (usually 5-7 μm thick), subrectangular shape, nexine outline elliptic to subrectangular, and medium-sized; type II has pollen with a thicker exine (11-18 μm thick), elliptic shape, nexine outline dumbbell-shaped, and large-sized. Subtype II 1 has columellae in the ectosexine, whereas subtype II 2 has a compact ectosexine. A palynologic alliance is established among the mutisiean genera Aphyllocladus, Gypothamnium, and Plazia (Plazia group), species of Onoseris and Urmenetea (Onoseris group), Brachyclados, Chaetanthera, Lulia, Mutisia, and Pachylaena (Mutisia group), Gerbera, Trichocline, and Uechtritzia (part of the Gerbera group), and Hyaloseris and Dinoseris on the basis of pollen similarities. These generic groups are defined by the habit and floral and fruit features, and the pollen structure is mainly useful to establish relationships among the groups. In this scheme the Mutisia group, which includes Chaetanthera, approaches the Onoseris and Gerbera groups.
... Bremer (1994) followed conclusions from cladistic studies by Karis et al. (1992) that Dicoma , Erythrocephalum, and Pleiotaxis were members of Mutisieae, and he maintained the genera as such under the informal Dicoma group. Cladistic studies of the Dicoma group by Ortiz (2000) using Oldenburgia and Gochnatia as outgroups, showed Erythrocephalum and Pleiotaxis to be sister to a paraphyletic Dicoma with the species of Pasaccardoa derived from within it. Subsequent studies by Ortiz (2001 Ortiz ( , 2006) refined the concept of Dicoma and the Dicoma group to contain also Cloiselia, Dicoma, Erythrocephalum, Gladiopappus, Macledium, Pleiotaxis, and Pasaccardoa. ...
Molecular studies of the flowering plant family Compositae (Asteraceae) based on comparative DNA sequence data of chloroplast genes provide new insights into the evolution and radiation of the family. The results support the creation of new groups to maintain a classification that reflects evolutionary history. We are proposing the following new names: subfamilies Corymbioideae, Gochnatioideae, Gymnarrhenoideae, Hecastocleoideae, and Pertyoideae; tribes Athroismeae, Corymbieae, Dicomeae, Gochnatieae, Gymnarrheneae, Hecastocleideae, Polymnieae; subtribe Rojasianthinae. The totals now stand at 11 subfamilies and 35 tribes. Only one tribe, the Mutisieae, is non-monophyletic having two branches. Most of the new groups are derived from taxa included in tribe Mutisieae, long suspected to be a paraphyletic group. Molecular studies that support these changes are discussed elsewhere but a summary of their results is presented.
... We are currently carrying out a monographic study of Dicoma and related genera of the Mutisieae from tropical and southern Africa (e.g. Ortiz & Rodríguez-Oubiña, 1994, 1996Ortiz, Rodríguez-Oubiña & Tadesse, 1998;Ortiz, 2000;Ortiz & Coutinho, 2001;Ortiz, 2001;Ortiz & Pulgar, 2002). In the course of this work we have carefully studied the material collected by Marloth on the Ga Mhana peak, Kuruman District, Northwest Province of South Africa. ...
During our revision of the genus Dicoma (Asteraceae, Mutisieae) from South Africa, we have carefully studied the remaining material of a collection made by Marloth from the Ga Mhana peak (Kuruman district), which we herein describe as a novel species. Until now this species has been misinterpreted as D. nachtigalii O. Hoffm. or left unclassified because of its lack of complete florets. In addition to the description of the new species, D. kurumanii, we discuss its relationships with D. cuneneënsis Wild and with D. nachtigalii, the most similar species of the genus. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 147, 509–513.
... Nevertheless, the existence of a continuous transition among the quantitative pollen characters of the Dicominae species we examined (Table 1) did not enable us to define two pollen types for this subtribe. On the contrary, we consider that our results support the existence of a large clade comprising the Macledium, Pasaccardoa, ''Dicomopsis'', Dicoma, and Cloiselia clades (Ortiz 2000; Ortiz et al. 2009), because the pollen grains of all these genera share important features, namely thick, more or less straight, dense supporting columellae , lalongate mesoapertures, and perforate (rarely rugulate-perforate) inter-spinular sculpture. The average values we found for the equatorial diameter (46.00 lm), the exine thickness (7.50 lm), and the ratio ''E/exine thickness'' (6.13) of the Dicomeae are quite close to those indicated by Bolick (1991) for both the MutisieaeTable 3 Pollen quantitative characteristics of some tribes related to the Dicomeae Tribe Pollen morphology in tribe Dicomeae 1861 (respectively: 43.10, 6.50, and 6.60 lm) and Cardueae (respectively: 49.10, 6.50, and 7.50 lm). ...
A taxonomic reevaluation of two little-knownBrimeura taxa,B. fontqueri (Pau)Speta andB. duvigneaudii (L. Llorens)Rosselló et al., has been made.Brimeura fontqueri, described from the Iberian peninsula, has been put into synonymy ofB. amethystina (L.)Salisb., since it could not be distinguished on morphological, anatomical or cytogenetic grounds.Brimeura duvigneaudii, from the Balearic Islands, is closely related toB. amethystina and has 2n=28 chromosomes. It differs from the latter by its naked bulbs lacking dark cataphylls, and its narrower leaves
and whitish corollas. Accessory chromosomes are reported for the first time in the genus. Karyological instability (with chromosome
numbers ranging from 2n=28 to 42) is reported for a population ofB. fastigiata (Viv.)Chouard. A key to the recognized taxa ofBrimeura is provided.
... Phytochemical investigations of D. anomala have identified several classes of secondary metabolites; including acetylenic compounds, phenolic acids, flavonoids, sesquiterpene lactones, triterpenes and phytosterols [14][15][16]. The investigation of a dichloromethane extract of the roots of D. anomala resulted in the isolation of asymmetrical sesquiterpene dimers with potent anti-plasmodial properties [17,18]. ...
Anti-malarial drug resistance threatens to undermine efforts to eliminate this deadly disease. The resulting omnipresent requirement for drugs with novel modes of action prompted a national consortium initiative to discover new anti-plasmodial agents from South African medicinal plants. One of the plants selected for investigation was Dicoma anomala subsp. gerrardii, based on its ethnomedicinal profile.
Standard phytochemical analysis techniques, including solvent-solvent extraction, thin-layer- and column chromatography, were used to isolate the main active constituent of Dicoma anomala subsp. gerrardii. The crystallized pure compound was identified using nuclear magnetic resonance spectroscopy, mass spectrometry and X-ray crystallography. The compound was tested in vitro on Plasmodium falciparum cultures using the parasite lactate dehydrogenase (pLDH) assay and was found to have anti-malarial activity. To determine the functional groups responsible for the activity, a small collection of synthetic analogues was generated - the aim being to vary features proposed as likely to be related to the anti-malarial activity and to quantify the effect of the modifications in vitro using the pLDH assay. The effects of the pure compound on the P. falciparum transcriptome were subsequently investigated by treating ring-stage parasites (alongside untreated controls), followed by oligonucleotide microarray- and data analysis.
The main active constituent was identified as dehydrobrachylaenolide, a eudesmanolide-type sesquiterpene lactone. The compound demonstrated an in vitro IC50 of 1.865 μM against a chloroquine-sensitive strain (D10) of P. falciparum. Synthetic analogues of the compound confirmed an absolute requirement that the α-methylene lactone be present in the eudesmanolide before significant anti-malarial activity was observed. This feature is absent in the artemisinins and suggests a different mode of action. Microarray data analysis identified 572 unique genes that were differentially expressed as a result of the treatment and gene ontology analysis identified various biological processes and molecular functions that were significantly affected. Comparison of the dehydrobrachylaenolide treatment transcriptional dataset with a published artesunate (also a sesquiterpene lactone) dataset revealed little overlap. These results strengthen the notion that the isolated compound and the artemisinins have differentiated modes of action.
The novel mode of action of dehydrobrachylaenolide, detected during these studies, will play an ongoing role in advancing anti-plasmodial drug discovery efforts.
... Warionia, as commented before, was included by some authors (Dimon, 1971; Cabrera, 1977; Dittrich, 1977) within the Mutisieae sensu lato. Some characters coincide with those of the African Mutisieae, principally with the members of the tribe Dicomeae (Ortiz, 2000Ortiz, , 2001), whereas many characters of Warionia show a departure from that group. A comparison between Warionia and the African Dicomeae shows that: (1) Leaves of Warionia are sinuate to pinnately-partite whereas all the African Dicomeae have entire leaves; (2) Warionia's involucre is rather similar to that of the core Dicomeae (Dicoma Cass., Macledium Cass., Cloiselia S. Moore, Pasaccardoa Kuntze) but its phyllaries are not coriaceous and have not an acuminatepungent apex as in those genera; (3) Warionia's corolla tube dilates abruptly into the limb (being very similar to that of the genera Pleiotaxis Steetz and Erythrocephalum Benth. ...
The genus Warionia, with its only species W. saharae, is endemic to the northwestern edge of the African Sahara desert. This is a somewhat thistle-like aromatic plant, with white latex, and fleshy, pinnately-partite leaves. Warionia is in many respects so different from any other genus of Asteraceae, that it has been tentatively placed in the tribes Cardueae, Cichorieae, Gundelieae, and Mutisieae. Until now, a comprehensive study of Warionia to have a complete context for discussing its taxonomic position is lacking. The general morphology, anatomy, palynology and chromosome number of W. saharae are investigated here, and the species is described and illustrated. Laticifers in leaves and stems indicate a relationship with Cichorieae, and are associated with the phloem, in contact with it or with the surrounding sclerenchyma sheath. The pollen features indicate a strong relation with Cardueae, namely the structure with Anthemoid pattern where the columellae are joined to the foot layer, the ectosexine with thin columellae, the endosexine with stout and ramified columellae, the conspicuous spines with globose bases and conspicuous apical channels, and the tectum surface very perforate. Chromosomal counts resulted in 2n = 34. The morphological and palynological evidence positions Warionia between the tribes Cardueae and Cichorieae suggesting that it could be a remnant of the ancestral stock that gave rise to both tribes.
... Bremer (1994) followed conclusions from cladistic studies by Karis et al. (1992) that Dicoma , Erythrocephalum, and Pleiotaxis were members of Mutisieae, and he maintained the genera as such under the informal Dicoma group. Cladistic studies of the Dicoma group by Ortiz (2000) using Oldenburgia and Gochnatia as outgroups, showed Erythrocephalum and Pleiotaxis to be sister to a paraphyletic Dicoma with the species of Pasaccardoa derived from within it. Subsequent studies by Ortiz (2001 Ortiz ( , 2006) refined the concept of Dicoma and the Dicoma group to contain also Cloiselia, Dicoma, Erythrocephalum, Gladiopappus, Macledium, Pleiotaxis, and Pasaccardoa. ...
The largest family of flowering plants Asteraceae (Compositae) is found to contain 12 major lineages rather than five as previously suggested. Five of these lineages heretofore had been circumscribed in tribe Mutisieae (Cichorioideae), a taxon shown by earlier molecular studies to be paraphyletic and to include some of the deepest divergences of the family. Combined analyses of 10 chloroplast DNA loci by different phylogenetic methods yielded highly congruent well-resolved trees with 95% of the branches receiving moderate to strong statistical support. Our strategy of sampling genera identified by morphological studies as anomalous, supported by broader character sampling than previous studies, resulted in identification of several novel clades. The generic compositions of subfamilies Carduoideae, Gochnatioideae, Hecastocleidoideae, Mutisioideae, Pertyoideae, Stifftioideae, and Wunderlichioideae are novel in Asteraceae systematics and the taxonomy of the family has been revised to reflect only monophyletic groups. Our results contradict earlier hypotheses that early divergences in the family took place on and spread from the Guayana Highlands (Pantepui Province of northern South America) and raise new hypotheses about how Asteraceae dispersed out of the continent of their origin. Several nodes of this new phylogeny illustrate the vast differential in success of sister lineages suggesting focal points for future study of species diversification. Our results also provide a backbone exemplar of Asteraceae for supertree construction.
Surface and some anatomical characteristics of mature cypselae in four genera and 12 species members of the subtribe Leiboldiinae were analyzed, through light and scanning electron microscopy, with the aims of testing their diagnostic value in the taxonomical delimitation, and for this reason also studied related genera of Vernonieae which corresponds to 13 genera and 15 species grouped in seven subtribes. In addition to performing a detailed description of cypselae surface and anatomical characteristics, their potential taxonomical value is discussed. Most Leiboldiinae have prismatic cypselae, but when combined with the number of ribs and surface characteristics, species or genera can be identified. For example, Stramentopappus has obovate glabrous cypselae without a carpopodium compared with the other members of this subtribe. Bolanosa has a sericeous glandular indumentum, and Leiboldia has glands at the base of the cypselae and reticulate primary sculpture. The species of Leiboldiinae and other subtribes of Vernonieae here studied with crystals have prismatic ones contrary to the ones previously described for the Neotropical Vernonieae that were considered raphides.
Ortiz, S. & Coutinho, A. P.: Achyrothalamus reduced to Erythrocephalum ( Asteraceae, Mutisieae ). – Taxon 50: 389–403. 2001. – ISSN 0040‐0262.
The monotypic genus Achyrothalamus has been conventionally distinguished from Erythrocephalum principally by the absence of a pappus and the presence of phyllaries with entire margins. However, a critical re‐examination of 83 morphological and anatomical characters, and a detailed study of the pollen of the two genera, suggest that recognition of Achyrothalamus as a distinct genus is unjustified. We thus propose Achyrothalamus as a synonym of Erythrocephalum with the new combination E. marginatum.
The subfamily Mutisioideae (74 genera, ca. 865 species), which comprises three tribes, Mutisieae (43 genera, ca. 500 species), Nassauvieae (25 genera, ca. 315 species), and Stifftieae (six genera, 48 species), is analyzed at the generic level. A total of 87 genera traditionally related to Mutisioideae were studied. The genera of Mutisioideae are described and illustrated, and keys to tribes and genera are given. Corollas, anthers, styles, and pollen, are analyzed and discussed. The styles (smooth, rugulose to papillose, papillae short and rounded) constitute the main characters for delimiting the subfamily. The presence and distribution of the style papillae support the recognition of three tribes, although other characters as corolla shape contribute to their definition. The pollen of Nassauvieae can be clearly differentiated from the pollen of Mutisieae and Stifftieae. The morphology supports the exclusion of Brachylaena, Cloiselia, Dicoma, Duseniella, Erythrocephalum, Gladiopappus, Hesperomannia, Macledium, Moquinia, Pasaccardoa, Pleiotaxis, Tarchonanthus, and Warionia but not the exclusion of other taxa, for example, Hecastocleis, the Gochnatia complex, or the Ainsliaea group members.
PhD Thesis (PhD (Botany and Zoology))—University of Stellenbosch, 2009. An intriguing biogeographic area that lies in northwestern Namibia and southwest Angola is known for having numerous endemic taxa. It had, however remained vaguely defined because of the complex flora, the arid environment and confusing and inconsistent use of biogeographic terminology. This thesis redefined the area as a centre of endemism based on recurrent patterns of plant distributions by shared species. The end result is a well-defined entity with regard to, not only geographic boundaries and floristic elements, but also to its history and floristic relationships. A vast amount of information on the plants of the area, their affinities and their distributions is required for a study of this nature and this was undertaken through literature surveys and field work. All the relevant information on Namibia and the southwestern Angolan flora, i.e. the region and the study area, were incorporated into a database which formed the bases for numerical analysis and GIS studies. The database also brought together a wide range of information from literature sources that included facts and theories about the past and present physical environment. The structure of the database permitted querying this electronic data in many different ways. To accommodate the wide variety of subjects in a logical way, the thesis was divided into two sections. Section A concentrated on the region and provided background information and context. The theory, terminology and phytogeographic studies in the region were evaluated as a first step. A large amount and variety of palaeo-environmental and palaeo-ecological information, pertinent to the region was incorporated. Secondly the flora was assessed. Besides the diversity, distribution patterns of the plants within and outside the region, including disjunct distributions, phylogenies were assessment. Finally taxa with similar geographic ranges were grouped. These entities were mapped and both the taxa and their environments were evaluated Section B focused on the core area, namely the Kaokoveld Centre of Endemism, which was delimited by numerical techniques, and then investigated further with regard to its floristic components, relationships and origins. The flora and endemic components are described in detail. The result is a well-defined centre of endemism which comprises one endemic family, 10 endemic genera and nearly 300 endemic species. The flora of the Centre includes about 1600 species in nearly 550 genera in 130 families. Three floristic Groups, identified in section A, that have a remarkable number of endemics are found in the Centre. Historical explanations for the distribution patterns were suggested and the Group that includes Welwitschia mirabilis Hook.f., has been shown to be linked to the Arid Corridor. The demand for accurate knowledge about biodiversity has been highlighted by the Convention of Biological Diversity and there are a remarkable number of users with different requirements today. This study provides a much needed alternate look at the plants of the region, as well as a summation of the principle phytogeographic elements of the Namibian flora. It also includes a new phytogeographic classification and map of the floristic Groups of Namibia, which will contribute to defining floristic areas in the region.
Farris, J. S. (Dept. Biol. Sci., State Univ., Stony Brook, New York 11790) 1969. A successive approximations approach to character
weighting. Syst. Zool., 18:374–385.—Characters that are reliable for cladistic inference are those that are consistent with the true phyletic relationships,
that is, those that have little homoplasy. A set of cladistically reliable characters are correlated with each other in a
particular non-linear fashion here referred to as hierarchic correlation. Cladistically unreliable characters can be hierarchically
correlated only by chance. A technique that infers cladistic relationships by successively weighting characters according
to apparent cladistic reliability is suggested, and computer simulation tests of the technique are described. Results indicate
that the successive weighting procedure can be highly successful, even when cladistically reliable characters are heavily
outnumbered by unreliable ones.
Studies of the aerodynamics of particle transport and capture suggest that the conditions most propitious for effective wind pollination are as follows: (1) production and release of large numbers of grains; (2) both anthers and stigma exposed; (3) grains falling within a certain size range (20-40μ); very small grains will be dispersed readily but cannot be captured efficiently by the stigma, large grains have a high terminal velocity, hence will settle too rapidly; (4) exine of grains thin (or with large air spaces), sculpture smooth; (5) the stigma should present much surface area to capture grains, but, since collection efficiency will decrease with increasing stigma diameter, the increase in surface should be accomplished through the evolution of a complex stigma with many branches of small diameter; (6) individuals of the species should not be too widely spaced in the vegetation; (7) the vegetation should be open in structure or deciduous; thus there will be few obstructions to transport during at least one portion of the year; (8) flowering must be closely coordinated by relatively unambiguous environmental stimuli; (9) pollen release (hence flowering) should coincide with the most favorable time of the year for transport (low probability of precipitation, adequate winds and turbulence, deciduous season). The geography of wind pollination in the angiosperms can be understood best in terms of these prerequisites for efficient transport of pollen. Anemophily is very infrequent in the tropical rain forest, becomes more frequent as one moves to more seasonally variable environments, and is frequent in northern temperate forests. The environment of the tropical rain forest is unsuitable for anemophily: (1) species diversity is very high, hence individuals of the same species are apt to be widely spaced; (2) the forest is densely structured, hence wind velocities are low and there are many obstacles to transport; (3) there is no leafless season; (4) rainfall is frequent throughout the year, hence transport will be limited; (5) there are few unambiguous stimuli which can coordinate flowering; (6) potential animal pollinators are abundant. These conditions do not exist in northern temperate forests, or in prairies, or in savannas. It is possible that the evolution of wind pollination in the angiosperms paralleled the evolution of the deciduous habit. Axelrod has suggested that the deciduous habit evolved in response to seasonal drought as angiosperms migrated into lower middle latitudes during the early Cretaceous. Both the deciduous habit and the physical conditions existing just peripheral to the tropics would favor the evolution of wind pollination. An examination of seasonal environments in the tropics at present and the fossil record of deciduous and wind pollinated angiosperms supports this contention.
Section Pterocoma is revised; its species are keyed out and enumerated, and Dicoma sessiliflora and D. zeyheri are discussed. Section Psilocoma is delimited and the Dicoma anomala species complex discussed. A new species, D. elliptica and a new subspecies, D. sessiliflora subsp. stenophylla, are described. Dicoma argyrophylla is reduced to subspecific rank under D. zeyheri, and Dicoma anomala var. attenuata S. Moore is raised to species level. A new subspecific combination is made for D. vaginata O. Hoffm. in D. kirkii Harv.
We present a cladistic analysis of 53 taxa from Asteraceae using 72 characters of mainly morphological data. Results reveal subfamily Cichorioideae is paraphyletic. The Mutisieae constitute a basal grade that contains monophyletic groups with Mutisia and Cardueae sensu lato. The Arctotideae, Liabeae, Vernonieae, and Lactuceae form a clade together with subfamily Asteroideae. Our results show some inconsistencies with those from cladistic analyses of molecular data.
A revision of the genus Dicoma (Asteraceae: Cichorioideae: Mutisieae) in the Horn of Africa (Djibouti, Eritrea, Ethiopia, and Somalia) is provided. This area is probably a major center of radiation for this genus, and nine of the twelve species present are endemic here. The revision is based on both field observations and micro- and macromorphological study of herbarium specimens. Six of the twelve species recognized have been described recently by the first two authors. For each species, data are presented on morphological characteristics, area of distribution (of particular interest in view of the incorrect information previously published for several of the species), ecology, and local names. One new species, D. thuliniana, is described and illustrated, one new combination, D. schimperi subsp. cinerea, is proposed, and D. lanuginosa is lectotypified.
Two new species,Dicoma gillettiiandDicoma scoparia(Asteraceae), both from Somalia, are described and illustrated. The differences between the new species and related taxa are listed.
Two new species of the genus Dicoma, D. popeana from Somalia and D. aethiopica from Ethiopia, both of the section Psilocoma, are described and illustrated. The two species are distinguished from D. anomala and other similar taxa by a morphologic diagnostic key.
Abstract— A cladistic analysis involving 27 tribes and subtribes of Asteraceae and 81 characters is presented. The terminal taxa are mainly those of present tribal classification, though some apparently poly- and paraphyletic tribes, notably the Mutisieae and the Inuleae, have been represented by sub-tribal taxa. Characters are assembled from all available sources. Corolla types, styles and stamens have provided many characters. The Lobeliaceae are used as an outgroup and are considered as the most probable sister group of the Asteraceae. There is a basal dichotomy in the family, the Mutisieae-Barnadesiinae being the monophyletic sister group of the remaining major, also monophyletic part of the family. The recent family division into two subfamilies about equal in size, the Cichorioideae and the Asteroideae, neither represents a basal dichotomy nor a sister group relationship within the Asteraceae. The Asteroideae are monophyletic and have their sister group within the paraphyletic Cichorioideae. Interrelationships among the cichorioid tribes are still unclear. The Lactuceae, Eremothamneae, Vernonieae and Liabeae may be one monophyletic group, and the Arctoteae, Carlineae, Echinopsideae and Cardueae another. The Mutisieae are a paraphyletic grade at the base of the family. Within the subfamily Asteroideae tribal interrelationships are also rather unclear. The Anthemideae and the Heliantheae sensu lato (including the Helenieae, Tageteae, Coreopsideae and all helenioid/helianthoid representatives sometimes placed in the Senecioneae) may be sister groups. The Heliantheae appear to be monophyletic and there is little support for the hypothesis that other tribes are derived from or have their sister group within the Heliantheae. The Astereae and the Eupatorieae may be sister groups, though a closer relationship between the Eupatorieae and the Heliantheae is possible. The Inuleae are a paraphyletic grade group at the base of the subfamily Asteroideae in the same way as the Mutiseae are a grade group at the base of the family.
The relationships within theAsteraceae-Asteroideae are scrutinized by means of cladistic analyses of morphological and chemical data. New data are presented, and novel interpretations of features previously used in cladistic analyses are made. Examples are insertion of anther filaments in the corolla, and morphology of disc floret styles, respectively. The results include a polyphyletic or paraphyleticInuleae s. l., and a paraphyleticHeliantheae s.l. in which theEupatorieae constantly form a subclade. Comparisons are made with previous cladistic analyses of morphological data, and those acquired from molecular data. Speculations about the evolution of certain organs are presented.
A cladistic analysis of the genusAnisopappus (Asteraceae: Inuleae) has been undertaken. A hypothesis of species interrelationships in the genus is presented for the first time. The analysis also includedArctotis (Arctoteae), used as outgroup, and five additional genera from theInuleae: Geigeria, Calostephane, Asteriscus, Buphthalmum, Pulicaria, andInula. It is concluded thatAnisopappus is a monophyletic group situated at the base of the tribe, diagnosed by, e.g., their obtuse stylar sweeping-hairs. The species with acute sweeping-hairs were found to be derived within the genus. Problems concerning species delimitation, biogeography and character evolution in the genus are briefly discussed.