JOURNAL OF THE ARNOLD ARBORETUMVoLUMI 62 JULY 1981 NUMBER 3 THE GENERA OF AMARANTHACEAE IN THE SOUTHEASTERN UNITED STATES' KENNETH R. ROBERTSON AMARANTHACEAE A. L. Jussieu, Gen. PI. 87. 1789, "Amaranthi," nom. cons. (AMARANTH FAMILY) Annual or perennial herbs, often woody at the base. infrequently lianas [or shrubs or trees]; stems erect to decumbent, trailing, or climbing, simpleor much branched, unarmed or rarely spinescent, glabrous to densely pubes-cent, [very rarely fleshy and/or articulated], usually from a stout taproot.Leaves alternate or opposite, simple and usually entire, sometimes undulate,infrequently serrulate or shallowly lobed. [very rarely reduced to scales orabsent], long-petiolate to sessile: stipules absent. Inflorescences of compactcymes or clusters arranged in axillary or terminal, simple or compound spikes.panicles, heads, or rarely racemes, or the flowers solitary; foliage leavesoften reduced and bractlike in the inflorescence: each flower subtended by1 bract and usually 2 bracteoles, all usually scarious, often spinescent. the Prepared for the Generic Flora of the Southeastern United States. a project ofthe Arnold Arboretum of Harvard University. This treatment follows the formatestablished in the first paper in the series (Jour. Arnold Arb. 39: 296-346. 1958).The area covered includes North and South Carolina, Georgia. Florida. Tennessee.Alabama, Mississippi, Arkansas, and Louisiana. The descriptions are based primarilyon the plants of this area, with additional information from extraterritorial taxa inbrackets. References that I have not seen are marked by an asterisk. This paper was initiated while I was at the Arnold Arboretum. but it has beenwritten largely with the generous support of the Illinois Natural History Survey. Inaddition to the libraries of the Arnold Arboretum and the Gray Herbarium, the libraryof the University of Illinois has been invaluable for checking the voluminous references.The libraries and herbaria of the Field Museum of Natural History and of the MissouriBotanical Garden were also utilized in this study, and specimens of Amaranthus were� President and Fellows of Harvard College, 1981.Journal of the Arnold Arboretum 62: 267-314. July. 1981.