Systematic Revision of the Epipetrum Group of Dioscorea (Dioscoreaceae) Endemic to Chile

Abstract

Epipetrum Phil. has long been considered one of the five narrow genera of Dioscoreaceae, comprising only three species endemic to Chile (Knuth 1924 ; Burkill 1960). Specimens of the most common species of this genus, collected by Bertero (1829) from Central Chile, were first described as Luzuriaga cordata Bertero, although the plant does not show any morphological affinities with the members of this unrelated genus of Philesiaceae. This misinterpretation was noticed by Colla (1836) who redescribed the species as Dioscorea humilis Colla, creating a nomenclatural conflict that has been recently clarified (Viruel et al. 2009). Dioscorea humilis was later transferred to a new genus, Epipetrum [ E. humile (Colla) Phil.] by Philippi (1862) after the rupicolous habitat of the plant. According to Philippi (1862 , 1864), the separation of this new genus from Dioscorea L. was justified by the absence of winged seeds. This remarkable trait is also shared with three other small genera of the yam family: the Mediterranean-Macaronesian Tamus L., which posseses a baccate fruit rather than a capsule (as in almost all other Dioscorea s. l. species), the Pyrenean Borderea Miégeville, and the Mexican Nanarepenta Matuda (Matuda 1961 ; Téllez-Valdés and Dávila-Aranda 1998), African Dioscorea gilletii Milne-Redh. (Milne-Redhead 1963), Caribbean Rajania L., and some other Dioscorea species with samaroid fruits. The combination of unwinged seeds produced in three-angled capsules, and a dwarf trailing habit shared with Borderea , led Pax (1887) to place E. humile within Borderea [ B. humilis (Bertero ex Colla) Pax], a classification later criticised based on morphological and biogeographical studies of Dioscoreaceae (Reiche 1908 ; Burkill 1960). None of the preceding nomenclatural combinations took into account the original and validly published specific epithet of this plant as L. cordata , and thus this epithet became substituted in the literature by the currently accepted one (humile), forcing the rejection of cordata to promote nomenclatural stability (Viruel et al. 2009). Despite the low taxonomic diversity within Epipetrum , the boundaries among some of its taxa are not completely clear.

Disrupted phylogeographical microsatellite and chloroplast DNA patterns indicate a vicariance rather than long‐distance dispersal origin for the disjunct distribution of the Chilean endemic Dioscorea biloba (Dioscoreaceae) around the Atacama Desert

“…This result is expected for two groups that are geographically separated by more than 600 km and by an inhospitable hyper‐arid area that establishes a significant geographical barrier to reproduction between both population groups, as revealed by the IBD analysis. While morphological (Viruel et al. , 2010a) and molecular data lend support for the recognition of both population groups as two subspecies of D. biloba , deciphering their origins can further contribute to understanding the evolutionary history of this endemic lineage of Dioscorea and its contribution to the biodiversity of Chilean mediterranean and arid areas.…”

“…1). These populations have been recognized as two subspecies by Viruel et al. (2010a): the northerly D. biloba subsp.…”

Morphological and molecular taxonomy of the annual diploids Anthoxanthum aristatum and A. ovatum (Poaceae) in the Iberian Peninsula. Evidence of introgression in natural populations

“…Subsequently, a canonical variate analysis (CVA) was computed to assess the distinction among the groups and the discriminatory power of variables (Hörandl, 2002). A classification discriminant test (CDA, cross‐validation) was also carried out to determine the group to which the classified OTU belongs with the highest probability (Legendre & Legendre, 1998; Repka, 2003; Marhold, Jongepierová & Kučera, 2005; Viruel et al ., 2010). Three different arrangements of populations were tested in CVA and CDA: (1) the four infraspecific taxa; (2) A. aristatum vs. A. ovatum ; (3) the sympatric Iberian populations vs. the respective allopatric A. aristatum and A. ovatum populations.…”

Diversification into novel habitats in the Africa clade of Dioscorea (Dioscoreaceae): erect habit and elephant’s foot tubers

“…and D. chouardii Gaussen; Fig. 3) from Pyrenean France and Spain, in the Epipetrum group from Chile [12], and D. hexagona Baker from Madagascar [13]. Leaves are always alternate and blades are entire to deeply palmately lobed.…”