A Revision of the Genus Schkuhria

Schkuhria is a member of the tribe Helenieae of the family Compositae.The problem of the correct generic name for this group of plants was considered by a Special Committee for Phanerogamae and Pteridophyta appointed by the 6th International Botanical Congress, Amsterdam, 193 5.The action of the committee relegates the Schkuhria Moench (1794) to synonymy under Siegesbeckia, rejects Tetracarpum Moench (1802), and validates Schkuhria Roth (1797).The type species is designated as S. abrotanoides Roth, Cat.Bot.1:116.1797. 2Asa Gray was one of the first to make valuable contributions to the knowledge of the genus in his "Notes on Compositae'' 3 , and his later revision in "Contributions to North American Botany" 4 .The next extensive revision of the genus was P. A. Rydberg's treatment of the North American species for the North American Flora 5 in which eight species were recognized as belonging to Tctracarpum y and a new genus, Cephalobembix y was created for S. multiflora.The most recent work on the genus is A. L. Cabrera's excellent paper on the Argentine species 6 .All in all, the genus has never been monographed, and since the time of Gray has not been treated in its entirety.The overlapping of morphological characters makes it difficult to separate several genera in the tribe Helenieae 7 .Nor has it been easy to separate Schkuhria