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Revision of the Dioecious Genus Chersodoma Phil. (Senecioneae, Asteraceae), Including a New Species and Status Change

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A revision of the dioecious genus Chersodoma (Senecioneae, Asteraceae) recognizes nine species, including a new species, C. deltoidea Sagast. and M. O. Dillon, from northern Peru and a status change for a northwestern Argentine endemic, C. glabriuscula (Cabrera) M. O. Dillon and Sagast. Chersodoma is confined to the Andean Cordillera and is the only dioecious member of the Senecioneae in continental South America. A cladistic analysis of a morphological data set supports the monophyly of the genus and the recognition of two previously established subgenera. Subgenus Chersodoma contains three species (C. argentina, C. candida, C. jodopappa) with greatest diversity in the semi-arid puna of northwestern Argentina and adjacent Bolivia and Chile. Subgenus Diclinanthus B. Nord., contains six species (C. antennaria, C. arequipensis, C. deltoidea, C. juanisernii, C. glabriuscula, and C. ovopedata) with greatest diversity in Peru. A key to Andean genera of Senecioneae is provided. A discussion of species relationships and historical biogeography is presented as suggested by morphological parsimony analysis.
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... Closely resembles C. juanisernii and is distinguished primarily by the sessile, amplexicaul distal leaves. Details: Dillon & Sagastegui (1996). ...
... Leaves lanceolate or elliptic, gray, tomentose, margins rolled down. Details: Dillon & Sagastegui (1996), Flora Argentina (2018ff.). ...
... Capitulescences solitary, the peduncles 3-9 mm long, 1-2-bracteolate, phyllaries 8-10, florets 10-20, achenes villous, pappus bristles white. Details: Dillon & Sagastegui (1996). ...
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The catalog describes 1362 species of ferns and flowering plants for the department of Arequipa, more than 200 species more as reported in the last systematic inventory by Quipuscoa, Dillon, & Ortíz in 2006. Ninety-five species are mentioned for the first time for Arequipa and 26 species mentioned in the literature for the department were excluded. In addition to a brief description of the species, the catalog includes information on their ecology, distribution, and human use. In addition to information on systematics and phylogeny, the most important synonyms are listed in the appendix.
... Chersodoma Phil. es un género endémico de América del Sur, con nueve especies (Dillon & Sagástegui-Alva, 1996). El mayor número de especies se encuentra en Perú (seis, Dillon & Hensold, 1993), seguido por Argentina (cuatro, Freire, 2008), Bolivia (tres, Hind, 2011;Jørgensen et al., 2014) y Chile (tres, Freire, 2008). ...
... Cuatrec. El papus es uniseriado, capilar, áspero (Cabrera, 1978;Dillon & Sagástegui-Alva, 1996). ...
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The purpose of this research is to describe two new species of Chersodoma from Bolivia: Chersodoma filifolia and C. tarijensis. Both species are small and caespitose shrubs; they differ in the number of florets per capitula, the indumentum of the leaves, and their geographic distribution: Chersodoma filifolia is known from central Bolivia and C. tarijensis from southern Bolivia. Additionally, a key for Bolivian species of the genus, a comparative table between the two new species and the most closely related species, and a map with the distribution of the two new species are provided.
... Géneros de Asteráceas estrictamente endémicos del Altiplano son Chersodoma, Parastrephia y Lophopappus. Para el caso de Chersodoma, Dillon & Sagástegui-Alva (1996) han propuesto un origen en el NW de Argentina, con una subsecuente diversificación hacia el Norte y el Oeste en los Andes. Desde la pre-puna argentina, el género se habría expandido hacia mayores altitudes por la zona del lago Titicaca hacia el norte de Perú. ...
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The family of the Asteraceae is the most diverse in the Chilean flora; nevertheless, only some tribes have undergone a recent systematic treatment, while the knowledge about the geographical distribution of the taxa is still very incomplete. From the review of herbarium specimens and fieldwork, a survey of the Compositae flora of the Arica y Parinacota Region was performed. The study shows the presence of 144 taxa of the Asteraceae family in the region of which 82.6% is native (119) and 9% is endemic to Chile (13), while 8.3% are considered as exotic species (12). The genus Senecio is the one showing the highest diversity in the region, with the presence of 27 species, including six endemic ones. The revision of the botanical material reveals the presence of five new species for the Chilean flora: Achyrocline ramosissima Britton, Gamochaeta humilis Wedd., Mniodes kunthiana (DC.) S.E. Freire et al. (=Lucilia violacea Wedd.), Pseudogynoxys cordifolia (Cass.) Cabrera, and Senecio evacoides Sch. Bip. A new species has been recently described based on our recent field surveys: Pseudognaphalium munoziae N. Bayón, C. Monti & S.E. Freire. Additionally, the correct denomination of the endemic species Stevia philippiana has been recently undertaken. The greatest diversity of species is found in the province of Parinacota, above 3,000 m asl. Compositae stand out in the region not only for its diversity but also as a crucial element of the vegetation, being a fundamental component of the precordillera and altiplano vegetation belts, known as "tolar", in which species pertaining to genera like Parastrephia, Lophopappus, Baccharis, or Senecio tend to dominate. Indeed, most of the vegetation belts described in the Parinacota province show members of the Asteraceae as dominant species. In spite of a big amount of the regional surface under formal protection, several species occur outside the protection units.
... In this case, according to Mayer & Charlesworth (1991), gynodioecy is cryptic, since pistillate flowers are difficult to identify, as their sexual organs are morphologically similar to the ones of hermaphrodite flowers. Gynodioecy is considered rare in the Asteraceae (Yampolsky & Yampolsky 1922), having been reported, for instance, to species of Bidens (Sun & Ganders 1987) and Chersodoma (Dillon & Sagástegui-Alva 1996). ...
Article
The Asteraceae have a high diversity of reproductive mechanisms, as shown by studies conducted mainly with species from temperate regions. Aiming to contribute knowledge on the reproduction of tropical species, we compared the floral biology and breeding systems of the co-occurring species Adenostemma brasilianum, Bidens segetum and Grazielia intermedia, and additionally identified their pollinators. The study was conducted in a seasonal semideciduous forest fragment in southeastern Brazil. Florets opened in early morning and were protandrous. In the first day of anthesis, secondary pollen presentation occurred during the staminate phase, mainly in the morning. In the same day, the pistillate phase began, being long in A. brasilianum and B. segetum (up to 4 days) and short in G. intermedia (1 day). Pollen viability was high in all three species, except for two G. intermedia individuals which showed male sterility, thus characterising a gynodioecious population. Self-compatibility was observed in A. brasilianum and self-incompatibility in B. segetum. In G. intermedia, besides sexual reproduction, apomixis was also observed. This is the first report of apomixis in the genus Grazielia. Although the studied species show distinct reproductive mechanisms, all of them benefitted from cross-pollination, which was mostly done by butterflies.
... The genus Chersodoma (Asteraceae) includes 9 species which occur exclusively in the Andean Cordillera [1] of which C. argentina Cabrera, C. candida Phil., C. glabriuscula (Cabrera), and C. jodopappa (Sch. Bip. ...
Article
Analysis of the hydrodistilled essential oil of the aerial parts of Chersodoma argentina Cabrera by GC-MS and NMR spectroscopy revealed that over 80% consisted of monoterpene hydrocarbons such as alpha-thujene, alpha-pinene and beta-pinene. Contact and headspace volatile exposure assays of the essential oil demonstrated antifungal activity against Sclerotinia sclerotiorum, Sclerotium rolfsii and Rhizoctonia solani with the contact assay showing greater activity than the headspace assay. Herbicidal activity was shown by reduced root growth of Allium porrum, Solanum lycopersicon and Sorghum halepense in both assays.
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Based on literature data, a list of new gynodioecious species of angiosperms within the world flora is composed, which includes 444 species from 61 genera and 49 families. By now, the gynodioecy has been detected in 1573 species, 364 genera, 97 families, and 36 orders of flowering plants. The features of gynodioecy distribution in the families such as Caprifoliaceae, Caryophyllaceae, Moraceae, Thymelaeaceae, Lamiaceae, Ericaceae are considered. It has been shown that there are two types of gynodioecious plants: the first group, where hermaphroditic individuals form only perfect flowers (the vast majority of gynodioecious species), and the second group, where hermaphroditic individuals have both pistillate and staminate flowers (family Moraceae). In the majority of gynodioecious species of the first group, a stable relationship is confirmed between the presence of gynodioecy in a taxon and such ecological and biological characteristics as a significant number of species in the genus, predominance of perennial herbaceous plants, and wide distribution in the temperate zone. Ecological correlations in gynodioecious species of the second group (family Moraceae), as well as in representatives of the families Thymelaeaceae and Ericaceae appear in close connection with another set of characters: tree life forms and distribution in subtropical and tropical floras.
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