Author : Harold Ernest Robinson
Publisher :
ISBN 13 :
Total Pages : 124 pages
Book Rating : 4.3/5 (243 download)
Book Synopsis Generic and Subtribal Classification of American Vernonieae by : Harold Ernest Robinson
Download or read book Generic and Subtribal Classification of American Vernonieae written by Harold Ernest Robinson and published by . This book was released on 1999 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Vernonieae in America is herein defined to exclude the Liabeae and Pseudostifftia (Moquinieae), and to include elements sometimes placed in the Heliantheae (Trichospira) or Lactuceae (Stokesia). Pollen, style bases, raphids, inflorescence form, involucre, anther appendage, and chemistry are some characters used in the reclassification. Tables 1-12 indicate the distribution of these characteristics in most American genera. Vernonia s.s., with type A pollen, is typified by V. noveboracensis (L.) and occurs in the Bahamas, eastern North America, south to central Mexico and has two species in temperate South America. All other species previously placed in Vernonia need to be removed from the genus, a process that is nearly complete for neotropical species. Most American Vernonieae seem to form a single related subgroup in the tribe. Subtribes included in the related subgroup are the Lychnophorinae (x 15, 17, 18) and Centratherinae (x 16) with type A pollen and furoheliangolides; Piptocarphinae (x 17) with type A pollen, deciduous inner involucre, and sometimes opposite leaves; Vernoniinae (x 17), many with glanduliferous anther appendages (including the Lepidaploa complex mostly with echinolophate pollen); and the newly proposed subtribes Sipolisiinae with type A pollen, armed receptacles, and carbonized achenes; Chrestinae with echinolophate pollen; and Leiboldiinae (x 19) with type A pollen, large heads, and a modified callus at the top of the achene. Of uncertain relationship to the preceding related subgroup are Stokesia (x 7), the Elephantopodinae (x 11, 13), and the Rolandrinae (x 8) with echinolophate pollen; three genera with type E pollen (Pacourina, Acilepidopsis, and Mesanthophora); and the Trichospirinae with type A pollen and flattened bicornute achenes. Ten subtribes are recognized, plus four unplaced generic groups. Three of the subtribal names, Leiboldiinae, Chrestinae, and Sipolisiinae are validated in the treatment. The genus Caatinganthus of eastern Brazil, a possible relative of the Elephantopinae, is described as new. A list of the 76 accepted genera of Vernonieae, native or introduced in the New World, is provided, and a complete list of names of American Vernonieae is given with an indication of their present taxonomic dispositions and geographical distributions. Fifteen new combinations are provided.
