944 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



pistillate, their corollas vestigial; inner flowers hermaphrodite, sterile; 

 achenes obovoid, long-villous. 



1. Oxytenia acerosa Nutt., Acad. Nat. Sci. Phila. Jour. ser. 2, 1: 

 172. 1848. 



Holbrook and Kayenta (Navajo County), Grand Canyon (Coco- 

 nino County), 3,300 to 5,800 feet, often on saline soil, July to Septem- 

 ber. Southwestern Colorado and New Mexico to Nevada and 

 southeastern California. 



A large, often leafless shrub with rushlike branches. Considered 

 by stockmen to be poisonous to cattle and sheep but seldom eaten. 



47. DICORIA 



Much -branched annual herbs, cinereous-strigose or -strigillose ; 

 leaves mostly alternate, ovate or suborbicular to lanceolate, toothed 

 or entire; heads small, very numerous, panicled, heterogamous and 

 disciform, or some of them unisexual and staminate; outer phyllaries 

 about 5, small, herbaceous, the inner ones (subtending the 1 or 2 

 pistillate flowers) subscarious, accrescent, much surpassing the outer 

 phyllaries at maturity; achenes dorso-ventrally flattened, oblong, 

 black, with a narrow or broad, toothed or pectinate, crustaceous, 

 whitish wing; pappus none or vestigial. 



Key to the species 



1. Mature achenes (solitary) surpassing the subtending phyllary; leaves linear- 

 lanceolate to lance-oblong; wing of the achene pectinately divided into 

 toothed lobes 1. D. brandegei. 



1. Mature achenes (1 or 2) shorter than the subtending phyllaries; upper leaves 

 elliptic to suborbicular, rarely oblong; wing of the achene merely toothed 

 to pectinately divided 2. D. canescens. 



1. Dicoria brandegei A. Gray, Amer. Acad. Arts and Sci. Proc. 11: 



76. 1876. 



Navajo and eastern Coconino Counties, doubtless also in Apache 

 County, about 5,000 feet, sandy soil, June to September. South- 

 western Colorado, southern Utah, and northeastern Arizona. 



It is stated that the Indians of northeastern Arizona used the 

 flowers and seeds as food. 



2. Dicoria canescens A. Gray in Torr., U. S. and Mex. Bound. Bot. 



87. 1859. 



Maricopa, Pinal, and Yuma Counties, doubtless elsewhere, up to 

 2,700 feet, sandy beds of streams and washes, June to November. 

 Southwestern Utah, Arizona, southeastern California, and Sonora. 



Specimens from near Tuba, Coconino County (Kearney and Peebles 

 12854), with oblong upper leaves and a comparatively narrow wing 

 to the achene, agree with Dicoria oblongifolia Rydb. It is not clear, 

 however, that D. oblongifolia is specifically distinct from D. canescens. 



48. HYMENOCLEA. Burrobrush 



Low, much -branched shrubs, monoecious or subdioecious; leaves 

 alternate, linear-filiform and entire, or pinnately parted into a few 

 linear-filiform lobes; heads small, those of both sexes usually inter- 

 mixed in the same leaf axils; pistillate involucre fusiform, beaked, 



