OXYTHECA POLYGONACE^E 575 



CHORIZANTHE 



gravelly bars along rivers Southern Oregon to California. 



E. vimineum Dougl. Benth. Trans. Linn. Soc. xvii, 416. Leaves 

 orbicular to broadly ovate, 3-10 lines broad, the margins often undulate, 

 loosely floccose-woolly above, densely white-tomentose beneath, on slender 

 petioles about as long as the blade : peduncles usually diffusely and repeat- 

 edly branching from near the base, 6-20 inches high: involucres narrow 

 and rather prismatic, \% lines long, the te^th very short : flowers rose- 

 colo v or yellowish, about a line long, outer segments obovate, the inner 

 only half as broad. On dry plains, Brit. Columbia to California east of 

 the Cascade Mountains. 



E. Baileyi Watson Proc. Am. Acad. x, 348. Leaves orbicular to 

 broadly ovate, 3-6 lines oroad, white-tomentose both sides, petioled: pe- 

 duncles diffusely branched 6-12 inches high, wholly glabrous: involucres 

 narrow, a line or less long, open at the throat, the teeth obtuse : flowers 

 pinkish-white, less than a Tine long. Dry plains eastern Washington to 

 Nevada and California. 



2 OXYTHECA Nutt. PI. Gambl. 169. 



Slender repeatedly dichotomously branched annuals with the 

 leaves all in a rosulate tuft and small involucrate flowers. Involu- 

 cres few-flowered, more or less pedicellate, campanulate or turbin- 

 ate, herbaceous and not reticulated, 3-5-cleft, the erect or spreading 

 lobes mostly terminated by straight slender awns. Flowers perfect ; 

 calyx 6-parted, colored, enclosing the achene: the more or less ex- 

 serted pedicels intermixed with bracts or bractlets. Achene, so far 

 as known, ovate-lenticular, the elongated radical accumbent upon 

 the rounded cotyledons. 



0. dendroidea Nutt. 1. c. Leaves linear-oblanceolate, hirsute, 6-18 

 lines long acute : scape-like stem usually 6-12 inches high very slender dif- 

 fuse and much branched from near the base, or stouter and less branched: 

 bracts unequal, without awns, linear-oblong to linear, or oblong-ovate in 

 the stouter lorms, the lower half-inch long or less, the upper much smaller, 

 all more or less united at base : involucres turbinate, 1-3 lines long, un- 

 equally 3-4-lobed, rather fleshy, acutely a^wned, those in the forks on 

 slender pedicels 1-4 lines long, the others more nearly sessile flowers light 

 rose-color, half a line long, outer segments fcbovate, the inner narrower 

 and shorter. On dry hillsides, southeastern Oregon to Wyoming and 

 Nevada . 



3 CHORIZANTHE R. Br. 



Low dichotomously branched plants with the leaves mostly 

 in a rosulate radical tuft, and small flowers in small involucrate 

 heads. Involucres tubular or funnelform, sessile, 2-6-angled or 

 costate, and 2-6-toothed or cleft, the divisions more or less divari- 

 cate and terminating in cusps or rigid, often uncinate, awns. 

 Flowers 1-3 in the involucre more or less exserted. Calyx 6-parted 

 or 6-cleft. Stamens 3, or 2, inserted on the base or more or lessad- 

 nate to the tube of the calyx, rarely on its throat. Styles linear, 

 with capitate stigmas. Achenes triangular beaked, Embryo with 

 inflexed or straight radicle. Ours all annuals. 



C. membranacea Benth. Trans. Linn. Soc. xvii, 416, t. 17. Lanosely 

 pubescent when young, glabrate in age: stems erect, 6-18 inches high, 

 sparingly branched above: radical and lower cauline leaves linear, obtuse, 



