REVISION OF DONIOPHYTON (COMPOSITAE, BARNADESIOIDEAE)

This revision describes, illustrates and documents morphological varia tion in Doniophyton (Compositae, Barnadesioideae), restricted to Argen tina and Chile. Two species are recognized, D. anomalum and D. weddell ii (sp. nova), possessing distinct morphological and chromosomal featu res, elevational tolerances, and nearly allopatric distributions. Doni ophyton weddellii occurs primarily in central to northern Andean Chile and Argentina from 1900-4000 m a. s. l.; D. anomalum is found princip ally in central-western Argentina and south into Patagonia at 0-1800 m a. s. l. Close relationship exists with Chuquiraga of subfam. Barnades ioideae. It is hypothesized that Doniophyton evolved out of Chuquiraga in the high central Andes between Chile and Argentina. It is suggeste d that D. weddellii differentiated first, correlating with an aneuploi d chromosomal decrease from n = 27 (in Chuquiraga) to n = 25. Further evolution and chromosomal decrease to n = 24 resulted in D. anomalum, with accompanying migration into southern Andes and Patagonia. Nomencl atural changes result from examination of protologues and type specime ns: Doniophyton anomalum replaces the commonly used name D. patagonicu m, and a new species, D. weddellii, is described for the taxon masquer ading under the routinely used superfluous name D. andicola.