Portal de Periódicos da CAPES

Taxonomy of American Atriplex

1956; University of Notre Dame; Volume: 55; Issue: 1 Linguagem: Inglês

10.2307/2422334

1938-4238

Grant Dukelow Brown,

Plant Parasitism and Resistance

On the first day of autumn in the year 1804, Captain Meriwether Lewis of the Lewis and Clark Expedition, collected a plant specimen at the Big Bend of the Missouri. This specimen was described later by Pursh (1814) as being a new species of the genus Calligonum L. in the Polygonaceae. Subsequently, Nuttall (1818) placed it in the Chenopodiaceae as a member of the genus Atriplex L. Thus began the discovery and describing of shrubby atriplices native to the United States. In Species Plantarum Linnaeus (1753) limited the concept of the genus Atriplex drastically by placing most of the species attributed to it by many of the early eighteenth century botanists into other genera of the Chenopodiaceae. The first post-Linnaean generic division of Atriplex was that of Obione, as proposed by Gaertner (1791). The constant character of the inverted ovule, described from the single species 0. muricata, was the basis for the division. In the United States it was accepted by Torrey as a valid proposal, and he described half of the species treated in this paper as members of the genus Obione. Watson (1871) favored Torrey's system in describing the species torreyi, but in 1874 he reduced Obione into synonymy under Atriplex. Hall (1923) gave Obione subspecific rank under Atriplex. A few European botanists, e. g. Moquin-Tandon (1840), Ascherson and Graebner (1913), and Ulbrich (1934), have retained Obione as a genus. Pterochiton was the next generic proposal to be advanced. Torrey and Fremont (1845) based its exclusiveness upon the longitudinally winged bract character of Atriplex canescens. Nuttall (1848) recognized the division, but otherwise Pterochiton has been considered as nothing more than a section or subgenus of Atriplex. Other generic divisions of the genus not directly related to the group treated in this paper have been reduced to synonymy under Atriplex by Standley (1916), and no attempt has been made by the author to substantiate or refute his treatment. The reduced genera include Halimus Wallroth (1822); Schizotheca Meyer (ex. Lindley 1846), not Schizotheca Ehrenberg (1832); Phyllotheca Nuttall (ex. Moquin-Tandon in de Candolle, 1849); Lophocarya Nuttall (e,x. Moquin-Tandon in de Candolle, 1849); Pterocarya Nuttall (ex. Moquin-Tandon in de Candolle, 1849), not Pterocarya Kunth (1824); Phyllocarpa Nuttall (ex. Moquin-Tandon in de Candolle, 1849), not Pbyllocarpus Riedel (1842); Theleophyton Moquixn-Tandon (in de Candolle, 1849); Armola Kirschloger (ex. Montandon, 1856); and Teutliopsis Celakovsky (1872). Ulbrich (in Engler & Prantl, 1934) has proposed three new generic divisions, all 'based on members described previously as Atriplex. No attempt has 'been made by the author to evaluate the proposals of Ulbrich,