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Chapter17
Dicomeae (Carduoideae)
Santiago Ortiz, Rodrigo Carbajal, Miguel Serrano and Antonio X. P. Coutinho
HISTORICAL OVERVIEW
The tribe Dicomeae comprises the majority of the African
and Malagasy genera traditionally included in Mutisieae,
with the notable exception of Gerbera L. and related taxa
(Homann 1893; Cabrera 1977). This group of eight genera
was considered by Jerey (1967) as one of the most distinct
within Mutisieae. Grau (1980) considered their testa highly
characteristic among other Mutisieae, although he did not
mention that the testas of species of Dicoma Cass. now in-
cluded in the genus Macledium Cass. are, in fact, similar
to those of other Mutisieae. Hansen (1991) suggested that
most of the genera of this group be moved from Mutisieae
to tribe Cynareae (Cardueae). His arguments for this in-
cluded (1) the cuticular ornamentation of corolla epider-
mal cells characterized by a “rugose pattern of longitudinal
bands” (“intestine like”, sensu Karis et al. 1992), not muti-
sioid; (2) corolla of disc orets bell-shaped, divided into a
narrow tube and a broader limb; (3) bilabiate owers with
upper limb lobes short and uncoiled or absent (except in
Gladiopappus Humbert, in which they are long and coiled;
Humbert 1963); (4) style branches with subapical sweeping
hairs (although this is not always the case in some genera
such as Macledium); and (5) achene turbinate or turbinate-
cylindrical and frequently with conspicuous ribs (although
this is not the case in Macledium and Pleiotaxis Steetz).
Bremer (1994) referred to this group of genera as
the Dicoma group”. He considered it to be one of the
most dicult groups to evaluate phylogenetically within
Mutisieae. According to his study, however, the species
of the Dicoma group are characterized by a corolla dis-
tinctly divided into a narrow tube and wide limb, a non-
mutisioid ray oret epidermial pattern, acuminate apical
anther appendages, and mostly subapically pilose style
branches. This group of genera was studied in a morpho-
logical phylogenetic analysis by Ortiz (2000), who con-
cluded 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 chloro-
plast DNA marker ndhF, concluded that some African
Mutisieae are more related to Cardueae than to Mutisieae
s.str. Their analysis placed the genera Cloiselia S. Moore
(Dicoma carbonaria (S. Moore) Humbert) and Pasaccardoa
Kuntze within a clade including the tribes Tarchonantheae
(Tarchonanthus L. and Brachylaena R. Br.) and Cardueae.
The topology of the phylogenetic tree obtained by
the analysis of Panero and Funk (2002, 2008), using
ten chloroplast DNA markers, supports the establish-
ment of new subfamilies and tribes from the paraphyletic
Mutisieae s.l. One of the new taxa proposed by these
authors is the tribe Dicomeae, which comprises most
of the African genera previously included in the tribe
Mutisieae. Panero and Funk (2002) also suggested that
Dicomeae and the tribes Tarchonantheae and Cardueae
constituted the subfamily Carduoideae, but they did not
have data for Oldenburgia Less. Funk et al. (2005) like-
wise proposed the tribe Dicomeae as the sister group of
the remaining members of Carduoideae but with the
relationship among Oldenburgia, Tarchonantheae and
Cardueae unresolved. Panero and Funk (2008) had two
results: (1) from a parsimony analysis Tarchonantheae
Ortiz, Carbajal, Serrano and Coutinho268
+ Oldenburgia form a clade that is in a polytomy with
Cardueae and Dicomeae; and (2) from the Bayesian anal-
ysis, which also places Tarchonantheae + Oldenburgia as
a clade but diers in that this clade is the sister group to
Dicomeae (Cardueae is the sister group to the other three
groups; this latter option does not have strong support).
Obviously, the relationships among these four taxa are
yet to be fully resolved. (See Chapter 44 for a complete
metatree.)
PHYLOGENY
With the aim of extending our understanding of the
phylogenetic relationships of Mutisieae s.l. of Africa and
Madagascar, Ortiz et al. (unpub.) performed various phy-
logenetic analyses using sequence data from ITS (rDNA)
and ndhF (cpDNA). In their parsimony analyses they
included a selection of genera from the basal groups of
Compositae.
Barnadesia
Chuquiraga
Dasyphyllum
Cnicothammus
Gochnatia
Wunderlichia
Stifftia
Pertya
Cloiselia
Dicoma
Echinops
Cirsium
Carthamus
Warionia
Lactuca
Arctotis
Liabum
Hesperomannia
Vernonia
Stokesia
Mutisia
Pachylaena
Chaptalia
Gerbera
Nassauvia
Trixis
Hecastocleis
Chaetanthera
67
99
100
75
95
74
96
66
62
100
66
88
100 96
100
92
100
General Africa
Tar.
Dic. Ol.
Oldenburgia
Tarchonanthus
Brachylaena
Eurasia
Central America, Caribbean
North America
Southern Africa
Madagascar, tropical Africa
Southern Andes, southern
South America
Eastern & central Asia
North & central Andes
North Africa, Mid Europe,
Mediterranean, South Europe
General Africa
Southern & southeastern Asia
Widespread or ambiguous
Fig. 17.1. The single most parsi-
monious cladrogram, based on
the joint analyses of ITS (rDNA)
and ndhF (cpDNA) sequences.
Three genera of Barnadesieae
and a broad selection of taxa
from Mutisieae s.l. were used
as outgroups. Cichorioideae
were used to represent the more
highly nested members of the
family. Numbers above lines are
boostrap values ( > 50). The col-
ors of the branches represent the
distribution of the taxa. Dic. =
Dicomeae; Ol. = Oldenburgieae;
Tar. = Tarchonantheae.
Chapter 17: Dicomeae (Carduoideae) 269
The tree produced using ndhF and ITS combined gives
the best basis for the discussion of not only Dicomeae
but also Tarchonantheae (Chapter 18) and Oldenburgieae
(Chapter 19) (Fig. 17.1). In this tree three genera from
Barnadesieae and a selection of genera from Mutisieae s.l.
were used as outgroups. Carduoideae (s.l.) are a mono-
phyletic group with Cichorioideae (s.str.) as sister. Of
course, because Cichorioideae here represent the remain-
der of the family, one must keep in mind that this diagram
tells us that Cardueae are sister to the rest of the fam-
ily and not the sister group of Cichorioideae. However,
the relationships among taxa of Cardueae are interesting
in that they agree with the Bayesian analysis of Panero
and Funk (2008), but with little support. Similar results
for the monophyly of Carduoideae were obtained from
the analysis using the ndhF marker alone (Ortiz et al.,
unpub.).
In the consensus tree obtained from analyses using the
ITS marker, the Dicomeae genera Macledium, Cloiselia,
Dicoma, and Pasaccardoa form one monophyletic group
while Pleiotaxis and Erythrocephalum form another. These
two clades fall in dierent locations based on the outgroup
used. In Fig. 17.2, the outgroup was Barnadesioideae and
the selected genera of Mutisieae s.l. and the two clades
of Dicomeae are in separate clades with the Pleiotaxis +
Erythrocephalum clade as the sister group of Warionia Bent h.
and Coss. and Lactuca L. In a separate analysis, when
only taxa from Mutisieae s.l. were used as outgroup, and
Barnadesioideae were excluded, both clades are in a poly-
tomy with Cichorioideae s.str. (representing all the rest of
the family), two thistle clades, and the Warionia + Lactuca
clade (Fig. 17.3). In both of these analyses the Oldenburgia
taxa and Tarchonantheae were located outside of the clade
containing Dicomeae (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) dierent genera (Ortiz 2000, 2001, 2006).
TAXONOMY
Tribe Dicomeae Panero & Funk in Proc. Biol. Soc.
Wash. 115(4): 916. 2002 Type: Dicoma Cass. (Figs.
17.5 –17.7 )
Perennial herbs, shrubs or small trees. Leaves alter-
nate, entire. Involucre hemispherical to obconic, pluri-
seriate, phyllaries often coriaceous and acuminate, pun-
gent. Receptacle alveolate, often epaleate, rarely paleate.
Capitula homogamous or heterogamous, solitary or often
arranged in lax corymbs or racemes, discoid or radiate.
Marginal orets white to red, bilabiate, with the inner
lips coiled or not, or ray; disc orets actinomorphic or
rarely zygomorphic, deeply 5-lobed; corolla white, yel-
low, cream to pink or mauve, glabrous to pubescent with
dierent types of glandular, or rarely eglandular, hairs;
anthers 5, caudate and calcarate, rarely ecalcarate, with
long tapering or subobtuse tails, ramied, with often
acute branches, rarely obtuse, these being retrorse along
the tail and lacking or antrorse at the apex, apical ap-
pendage acute to acuminate, endothecial tissue polarized,
pollen smooth to echinate; style short or long bid, with
Erythrocephalum
Dicoma
Pasaccardoa
Cloiselia
Macledium
Pleiotaxis
Warionia
Stokesia
Carthamus
Arctotis
Lactuca
Liabum
Hesperomannia
Vernonia
Cirsium
Echinops
Hecastocleis
53
53
84
84
99 100
76
General Africa
Fig. 17.2. Part of the strict consensus
tree of three equally most parsimoni-
ous 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.
Cichorioideae were used to represent
the more highly nested members of the
family. Numbers above lines are boot-
strap values ( > 50). The colors of the
branches represent the distribution of
the taxa. The genus Oldenburgia and the
tribe Tarchonantheae formed a mono-
phyletic group that was the sister group
to the clade shown here. See Fig. 17.1
for color chart.
Ortiz, Carbajal, Serrano and Coutinho270
The remaining three genera are rather dierent from
this core group of Dicomeae and were included in this
tribe by Panero and Funk (2002, 2008), based only on
morphology, since they were not able to include material
of these genera in their phylogenetic analysis. Pleiotaxis
and Erythrocephalum form a monophyletic group, mor-
phologically quite dierent from the other genera, and
in view of the phylogenetic analysis using ITS are either
unresolved in their relationship or are situated outside
Dicomeae. These genera show various characters that
separate them from the remaining genera of Dicomeae,
including phyllaries not pungent, anther tails with sub-
acute to subrounded apex, style branches separate and
often curved, achenes narrowly ellipsoid and with car-
popodium, and testa of the Erythrocephalum type (Grau
1980) (Fig. 17.5). Further molecular analyses will be nec-
essary to conrm or reject this position and to perhaps
delimit an additional tribe for these genera within the
African Mutisieae assemblage.
Regarding Gladiopappus, no one has yet obtained re-
cent collections of this taxon, and hence no sequence data
are available. Morphologically it diers markedly from
the core group of Dicomeae, including phyllaries with
rounded apex, presence of unisexual orets among the bi-
sexual disc orets, marginal orets of the capitula true bi-
labiate with coiled adaxial lobes, and achenes without twin
hairs. Thus, its inclusion within Dicomeae is provisional.
In view of the above, we can therefore tentatively rec-
ognize the following genera within the tribe Dicomeae:
Dicoma Cass. is the largest genus of the tribe, with
nearly 30 species of annual and perennial herbs, shrubs
and small trees (Figs. 17.5A–C, 17.6). This genus was split
the branches subacute to rounded, separating or not, with
apical or subapical, acute sweeping hairs and the stigmatic
area cover ing the entire ventra l side. Achene often obcon-
ical but also narrowly oblong to broadly cylindrical, con-
spicuously ribbed or not, sometimes with an apical groove
below the insertion of the pappus, often densely covered
by twin eglandular hairs with a dichotomous apex and
sometime with supercial glands between the ribs or all
around the achene; pappus of scabrid to plumose bristles
or scales, isomorphic or dimorphic, persistent, rarely ab-
sent or caducous, testa of Dicoma, Erythrocephalum, Perezia
Lag., Gochnatia type (Grau 1980) or Dicoma welwitschii
type (Ortiz 2000).
Panero and Funk (2002) recognized seven genera
in their tribe Dicomeae: Dicoma, Macledium, Cloiselia,
Pasaccardoa, Pleiotaxis, Erythrocephalum, and Gladiopappus.
The rst four genera form a monophyletic group, as noted
above, and seem very closely related to each other morpho-
logically. They share many characters, including: pungent
phyllaries without resin ducts or these reduced; presence
of star-shaped calcium oxalate crystals in the corollas, an-
ther laments and styles; anther tails long tapering; pol-
len slightly echinate; style branches straight and adjacent;
and achenes broad and without a carpopodium. Also re-
lated to this group is the unpublished genus “Dicomopsis
from the Angolan plateau, which shares some characters
with Pasaccardoa and some with Dicoma, and which also
has some exclusive characters such as distinctive achene
and testa morphology. This new genus would include the
principally Angolan species Dicoma welwitschii O. Hom.
(also present in the Democratic Republic of Congo), and
Pasaccardoa baumii O. Hom.
Erythrocephalum
Dicoma
Pasaccardoa
Cloiselia
Macledium
Pleiotaxis
Warionia
Stokesia
Carthamus
Arctotis
Lactuca
Liabum
Hesperomannia
Vernonia
Cirsium
Echinops
Hecastocleis
80
81
97 100
70
Fig. 17.3. Strict consensus tree of
eight equally most parsimonious
cladrograms, based on the analysis
of ITS (rDNA) sequence (Ortiz et
al., unpub.). A broad selection of
taxa from Mutisieae s.l. was used as
outgroups. Cichorioideae were used
to represent the more highly nested
members of the family. Numbers
above lines are bootstrap values
( > 50). The colors of the branches
represent the distribution of the
taxa. The genus Oldenburgia and
the tribe Tarchonantheae formed a
monophyletic group that was sister
to the clade shown here. See Fig.
17.1 for color chart.
Chapter 17: Dicomeae (Carduoideae) 271
by Ortiz (2000) in view of its paraphyletic character if
Pasaccardoa is not included and the marked synapomorphies
that support the main subgroups recognized by Ortiz’s
morphological phylogenetic analysis (Fig. 17.4). Some of
the diagnostic features of this genus are phyllaries with
conspicuous midrib and longitudinal dark stripes, style
branches long, achenes with supercial glands on the ribs
and twin hairs between the ribs, and testa of the Dicoma
type (Grau 1980). The monotypic genus Hochstetteria DC.
(D. schimperi (DC.) Baill. ex Hom.) should, in our opin-
ion, be included in Dicoma, as proposed by Hansen (1991)
and Bremer (1994), and as supported by the phylogenetic
analysis of Ortiz (2000).
Macledium Cass. includes 20 species of perennial
herbs and shrubs (Fig. 17.7A–C). Following the above-
mentioned phylogenetic analysis by Ortiz (2000), the
same author (2001) reinstated this genus, well character-
ized with respect to Dicoma by many characters, including
innermost phyllaries entirely scarious and shorter than the
contiguous outer series, marginal vascular tissue of co-
rolla lobes broad and surrounded by sclerenchymal bers,
achenes without supercial glands and with twin hairs
bulbous-glandular at the base and distributed all around
the achene, and testa of the Gochnatia type.
Cloiselia S. Moore is a reinstated genus of shrubby to
arboreal species endemic to Madagascar (Fig. 17.5E). In a
Fig. 17.4. Principal
monophyletic
groups recognizable
in the clade that
includes Dicoma s.l.
and Pasaccardoa in
the phylogenetic
analysis of Ortiz
(2000).
Ortiz, Carbajal, Serrano and Coutinho272
Fig. 17.5. Dicomeae.
A–C Dicoma tomentosa Cass.:
A habit, B oret, C achene
with pappus; D Pleiotaxis
rugosa O. Hom., habit;
E Cloiselia carbonaria
S. Moore., habit. [A–C,
redrawn from Flora of
Ethiopia and Eritrea 4(2):
12 (2004) by Alfredo
López; D, redrawn from
García de Orta, Série de
Botanica 17: 171 (2006) by
Alfredo López; E, redrawn
from Systematic Botany 31:
4 (2006) by Luis Orellana.]
Chapter 17: Dicomeae (Carduoideae) 273
Fig. 17.6. Dicoma. A Dicoma schinzii O. Hom. (Namibia: Funk and Koekemoer 12702); B, E Dicoma capensis Less. (Namibia:
Funk and Koekemoer 12664); C Dicoma elegans Welw. ex O. Hom. (Angola: S. Ortiz et al. 881); D Dicoma welwitschii O. Hom.
(Angola: S. Ortiz et al. 861); F Dicoma welwitschii O. Hom. (Angola: S. Ortiz et al. 866). [Photographs: A, B, E, V.A. Funk; C,
D, R. Carbajal; F, S. Ortiz.]
Ortiz, Carbajal, Serrano and Coutinho274
systematic review, Ortiz (2006) recognized four species.
Cloiselia shows a few characters that are otherwise almost
exclusively seen in certain primitive South American
Asteracean groups, namely the tribe Barnadesieae and the
Stenopadus group (tribe Stitieae) of the tribe Mutisieae
s.l. These characters are: corolla zygomorphic, generally
tubular, with ve lobes, and often with one sinus much
longer than the others; marginal nerves of the adjacent
lobes separate from the corolla base, rather than joined
until near the sinuses as is usual in Compositae; corolla
often villous, with long eglandular (not twin) hairs; sta-
mens inserted at the corolla base, and adjacent anther tails
connate. A priori, this might be taken to suggest some
sort of relationship between Cloiselia and these other
groups; however, in view of the dierent phylogenetic
studies cited above, it must be concluded that these appar-
ently plesiomorphic characters could be a result of isola-
tion and protection from competition, as seen in many
other plant and animal lineages on Madagascar. Besides
these characters, others clearly separate this genus from
the other genera of the Dicomeae core group, including
corolla much longer than the involucre, anthers protrud-
ing beyond the corolla, style with four veins, achenes with
supercial glands in a continuous layer, testa of the Perezia
type (Grau 1980), and pappus overtopping the involucre
and spreading at maturity.
Pasaccardoa Kuntze includes three species of suf-
frutescent and annual herbs. It is well characterized with
respect to the previous genera by its disc corolla tube
abruptly dilating into the limb, corolla lobes with scleri-
ed margins, disc oret achenes ellipsoid, achenes of mar-
ginal orets with a rostrum, twin hairs of the achenial
base conspicuously larger than those of the other parts of
the achene, and supercial achene glands situated in the
intercostal grooves. It has a testa of the Gochnatia type
(Grau 1980), rather similar to that of Macledium. As noted
above, P. baumii O. Hom., known from the Angolan
provinces of Bie and Kuando-Kubango, should be in-
cluded in the unpublished genus “Dicomopsis”.
Pleiotaxis Steetz includes about 25 species of peren-
nial herbs and subshrubs, with annual stems from woody
rootstocks (Figs. 17.5D, 17.7D). The principal diagnostic
characteristics of this genus are the phyllaries with sub-
acute to rounded apices (in Dicomeae this type of phyl-
lary is only present in Gladiopappus and two species of
Erythrocephalum), anther tails ecalcarate, and achenes nar-
rowly cylindric. Within this genus are two easily recog-
nizable dierent groups: one of them with capitula soli-
tary or in lax corymbs and with purplish orets, the other
with capitula arranged in panicles and with yellowish
to cream orets. These two groups should probably be
treated as sections or subgenera.
Erythrocephalum Benth. comprises about 14 species
of annual herbs or subshrubs, with annual stems from
woody rootstocks. It is well characterized by phyllaries
generally long-acuminate and dentate-lacerate, recep-
tacle paleate, achenes broadly ellipsoid with bifurcat-
ing twin hairs, and a pappus that is caducous or absent.
Ortiz and Coutinho (2001) suggested that Achyrothalamus
O. Hom., with its sole species A. marginatus O. Hom.,
should be included in the genus Erythrocephalum. These
authors found that the only important dierence with
Erythrocephalum was the absence of pappus, whereas the
remaining 82 characters studied were almost entirely
coincident. Phyllary apex morphology has been used
previously as a valid character by which to segregate
Achyrothalamus (obtuse and entire phyllaries), in con-
trast to phyllaries being acute and dentate-lacerate in
Erythrocephalum. Erythrocephalum jereyanum S. Ortiz &
Rodr. Oubiña, however, described from Tanzania, shows
all the normal characteristics of the genus but with ob-
tuse and entire phyllaries (Ortiz and Rodríguez-Oubiña
1998), invalidating the ecacy of this character.
Gladiopappus Humbert is a monotypic genus en-
demic to Madagascar. As indicated above, its morpho-
logical dierences from the Dicomeae core group are
marked, principally the phyllaries with rounded apices,
bilabiate marginal orets with coiled adaxial lobes (as is
normal in many true American Mutisieae), and presence
of unisexual orets in addition to bisexual orets of the
disc. The morphology of disc corollas, stamens, style and
achenes, however, are similar to those of the core group.
MORPHOLOGY
With its current denition, including all the genera cited
above, the tribe Dicomeae is morphologically heteroge-
neous. Nevertheless, the tribe as delimited could be de-
ned by a combination of features including: involucral
phyllaries pluriseriate; capitulum disc with bisexual o-
rets, these with long lobes and bell-shaped corollas; co-
rolla epidermal cell cuticle ornamentation longitudinally
striate and transversely ondulate to nearly smooth; en-
dothecial tissue polarized; anther appendage acuminate to
apiculate; anther tails long and with retrorse branches; and
styles with narrow, acute sweeping hairs. Alternatively,
if the last three genera (Pleiotaxis, Erythrocephalum, and
Gladiopappus) not belonging to the core group are ex-
cluded, morphological delimitation of the tribe would be
clearer, as discussed above.
POLLEN
In accordance with Wodehouse (1929), Stix (1960),
Perveen (1999), and Coutinho and Ortiz (in prep.), pollen
grains of tribe Dicomeae (all genera except Gladiopappus
Chapter 17: Dicomeae (Carduoideae) 275
Fi g. 17.7. Macledium and Pleiotaxis. A Macledium zeyheri (Sond.) S. Ortiz (South Africa, Gauteng: Funk and Koekemoer 12431); B
Macledium plantaginifolium (O. Hom.) S. Ortiz (Angola: S. Ortiz et al. 879); C Macledium plantaginifolium (O. Hom.) S. Ortiz
(Angola: S. Ortiz et al. 879); D Pleiotaxis rugosa O. Hom. (Angola: S. Ortiz et al. 840). [Photographs: A, V.A. Funk; B, S. Ortiz;
C, J. Rodríguez-Oubiña; D, R. Carbajal.]
Ortiz, Carbajal, Serrano and Coutinho276
which was not studied) are isopolar, radially symmetrical,
sub-oblate to prolate (P / E = 0.86–1.46), elliptic to sub-
circular in meridian optical section, sub-circular in equa-
torial optical section, acaveate, 3-zonocolporate, with a
tripartite apertural system (ecto-, meso-, and endoaper-
ture). The ectoapertures (colpi) are 12.0–40,5 µm long,
sub-terminal, the mesoapertures lolongate or lalongate,
and the endoapertures (ora) lolongate or lalongate, 9.4–
25.0 µm wide. The exine is 4.7–13.0 µm thick, the sexine
(1–)1.5–2 times thicker than the nexine, with a struc-
tured, micro-perforated tectum and an anthemoid pat-
tern. Sculpture is micro-echinate or echinate, with spines
widely conical, acute or blunt at the apices. P = 34–75
µm, E = 3367 µm.
CHROMOSOME NUMBERS
Dicoma: D. tomentosa Cass., n = 11 (Bhandari and Singhir
1977; Razaq et al. 1988); D. schimperi, n = 10 (Khatoon
and Ali 1993); D. schinzii O. Hom., 2n = 22 (Goldblatt
1989). Pleiotaxis: P. huillensis O. Hom. subsp. huillensis,
2n = 20 (Paiva and Leitao 1989).
CHEMISTRY
Several sesquiterpene lactones (germacranolides, eudes-
manolides and elemanolides) have been identied from
Dicoma s p ec i e s of s o ut h e r n A f r i c a by Z d e ro a n d B oh l m a n n
(1990). Several acetylene compounds of Pleiotaxis rugosa
O. Hom. were studied by Bohlmann and Zdero (1982),
who concluded that this genus is more closely related to
Cardueae than to Mutisieae, because it has compounds
including certain acetylenes and guaianolides that are
typical of the former tribe.
ECOLOGY
Species of Dicomeae most commonly occur in desert to
semi-desert bushlands or grasslands, miombo woodlands,
and open woodlands and grasslands; more rarely they are
found in swamp forests and on rocky outcrops and coastal
clis. Dicoma tomentosa Cass. behaves like a weed.
BIOGEOGRAPHY
The tribe Dicomeae is widely distributed in tropical Africa,
from Senegal and Egypt in the north to southern Africa
and Madagascar. It is also present in Asia, where there are
two species of Dicoma: D. tomentosa in India and Pakistan,
and D. schimperi in the Arabian Peninsula (Table 17.1).
Countries with the highest diversity and most endemic
taxa are: Angola (high diversity and numerous endem-
ics in the genera Macledium, Pleiotaxis, Pasaccardoa and
Dicoma), Democratic Republic of Congo (high diversity
in Macledium, Pleiotaxis, Pasaccardoa and Erythrocephalum,
with many endemics in Pleiotaxis), and Tanzania (high
diversity and many endemics in Erythrocephalum). Other
countries such as Zambia (with high diversity but few
endemics) and South Africa and Somalia (both with high
diversity and many endemics in Dicoma) are also worth
noting (Table 17.2).
EVOLUTION
It is not easy to nd a relationship between the African
tribe Dicomeae and the most primitive Compositae,
which for the most part are American. Certainly, the
Madagascan genus Cloiselia shows some characters that
are otherwise almost exclusively seen in certain primi-
tive South American Compositae. These plesiomorphic
characters, however, could probably be a result of paral-
lelism in isolation in Madagascar. In accordance with the
hypothesis presented in other chapters of this book (see
introductions to Chapter 12, Mutisieae s.l. and Chapter
20, tribe Cardueae) an origin of Cardueae occurred
when Africa was covered by Tertiary forests. It is prob-
able that the most mesophyllous members of Dicomeae
(e.g., Pleiotaxis) originated at the end of the Tertiary and
the more xerophyllous plants (e.g., many of the species of
Dicoma and Pasaccardoa) probably originated when a pro-
gressive deforestation and desertication of Africa was
happening.
Ta bl e 17.1. Geographical distributions of the genera of Dicomeae.
Genus Distribution
Cloiselia S. Moore Madagascar
Dicoma Cass. Widely distributed in tropical and
southern Africa, Madagascar, Arabian
Peninsula, India and Pakistan
Erythrocephalum Benth. Tropical Africa: from Kenya to Angola
and Mozambique
Gladiopappus Humbert Madagascar
Macledium Cass. Widely distributed in tropical and
southern Africa and Madagascar
Pasaccardoa Kuntze Tropical Africa: Tanzania, Democratic
Republic of Congo, Zambia and
Angola
Pleiotaxis Steetz Widely distributed in tropical Africa
and southern Africa (Namibia and
Botswana)
Chapter 17: Dicomeae (Carduoideae) 277
ETHNOBOTANY
Roots of Dicoma anomala Sond. subsp. anomala are used
in Zambia (Fowler 2006), Zimbabwe (Gelfand et al.
1985) and South Africa (Watt and Breyer-Brandwijk
1962) as a remedy for fever. Dried and powdered tissue
of Macledium sessiliorum (Harv.) S. Ortiz subsp. sessili-
orum and M. kirkii (Harv.) S. Ortiz were successfully
used in Malawi to protect stored grain against insects
(Chimbe and Galley 1996), while the whole plants of
the other subspecies (M. sessiliorum subsp. stenophyl-
lum (G.V. Pope) S. Ortiz) is very bitter and used as a
febrifuge, particularly for children, in Nigeria (Burkill
1985). Root decoctions and leaf juice of Erythrocephalum
longifolium Oliv. are dru n k a s an antima l a r ial in Ta nzania
(Haerdi 1964).
Acknowledgements. Our thanks go to Luis Orellana for the
illustrations, to Guy Norman for the English translation, and to
the sta of the herbaria BM, BOL, COI, K, LISC, LISU, NBG
and S where we have worked on the African Mutisieae s.l. over
the years. We also thank J. Mauricio Bonifacino who helped
with the trees and the photographic plates.
Table 17.2. Distribution of the species of Dicomeae by countries and genera (considering only those genera with more than five species).
Country/Genus Dicoma Macledium Cloiselia Pasaccardoa Pleiotaxis
Erythro-
cephalum
Gladio-
pappus Tota l
Angola 10(4) 7(2) 02(1) 16(9) 2(1) 037(17 )
Botswana 6 0001007(0)
Dem. Rep. Congo 27(1) 0322(11) 3037(12)
Madagascar 1(1) 1(1) 4(4) 0001(1) 7(7 )
Malawi 2 40013010(0)
Mozambique 4 40012011( 0)
Namibia 9(1) 10010011(1)
Somalia 10(8) 00000010(8)
South Africa 12(5)6(5) 0000018(10)
Tanzania 2 5 0 1 6(1) 11(5) 025(6)
Zambia 4 6 0 39(1) 2 0 24(1)
Zimbabwe 6 1001209(0)
Number of endemic species shown in parentheses. The three countries with highest diversity are shown in bold; in addition, for each
genus the three highest species numbers are shown in bold.
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