BUCKWHEAT FAMILY. 129 



3. CHORIZANTHE R. Br. 



Low, dichotomously branched annual herbs of summer, with rosulate radical 

 leaves (which disappear early in the dry season). Cauline leaves opposite or 

 ternate, frequently reduced and bracteate, the bracts sometimes unilateral. 

 Involucres (in ours) 1-flowered, tubular or funnelform, always sessile, 3 to 6- 

 angled or -costate, and 3 to 6-toothed or -cleft; teeth divaricate, cuspidate or 

 awned, the awns very frequently with a hooked tip. Flowers pedicellate or 

 nearly sessile, ebracteolate, included within the involucre or the segments pro- 

 trading. Calyx 6-parted or -cleft, often colored, never herbaceous. Stamens 

 usually 9 (seldom 3 or 6), adnate to the base of the tube. Ovary glabrous. 

 Embryo with inflexed or straight radicle. (Greek chorizo, to divide, and 

 anthos, flower, on account of the parted perianth.) 



Involucral teeth equal or the three alternate shorter. 

 Erect plants. 



Calyx-segments equal, nearly distinct; involucre with broad scarious margin 



1. C. membranacea. 



Calyx-segments very unequal, the alternate shorter; involucral margin none 



2. C. valida. 



Calyx shortly cleft, segments equal; involucral margin none or scanty.... 3. C. robasta. 



Erect' or diffuse plants; involucral margins pink or white; calyx shortly cleft; segments 



equal 4. C. douglasii. 



Prostrate plants. 



Calyx-segments unequal 5. C. polygonioidcs. 



Calyx-segments equal. 



Involucre usually margined; stamens 9 6. C. pungens. 



Involucre not margined; stamens 3 7. C. clevelandii. 



Involucral teeth very unequal, 1 long and 5 very short; prostrate 8. C. uniaristata. 



1. C. membranacea Benth. Erect, 6 to 14 in. high, unbranched, or once 

 or twice dichotomous at the summit of the stem ; herbage lanate throughout, 

 floccose in age, the upper surface of the leaves glabrate ; internodes about 2 

 in. long; leaves % to 1*4 in. long, linear, sessile, or gradually narrowed into 

 a short petiole; involucres condensed into dense head-like cymes, these solitary 

 in the upper axils and terminating the branches; margin of the involucre 

 wholly scarious between the awned teeth ; awns slender, uncinate, and strongly 

 divergent; flowers 2 or 3, of these 1 or 2 undeveloped or nearly obsolete; 

 calyx-segments distinct, broadly obspatulate with long, narrow claw. 



Inner Coast Range from the Vaca Mts. to Mt. Diablo. 



2. C. valida Wats. Erect, 4 to 6 in. high, once or twice di- or tri-choto- 

 mously branched; leaves spatulate; involucral teeth or lobes not margined 

 but awned; awns mostly straight; inflorescence similar to the preceding; flowers 

 pedicellate, partly exserted; calyx-segments oblong, erose-denticulate, hirsute 

 along the back on the midvein, very unequal (the alternate only y 2 as l° u g-) 



Sonoma; ivtaluma; Russian River. Rarely collected. 



3. C. robusta Parry. Stout, erect, 6 to 24 in. high, ternately and dicho- 

 tomously branched above, the stem below bearing two or three whorls of spatu- 

 late leaves, 2 in. long or less; heads large, dense, mostly terminal or sub-ter- 

 minal; involucre with narrow margins or none, teeth mostly uncinate, the alter- 

 nate shorter; calyx cleft % the way down, slightly exserted or not at all; 

 segments equal, oblong, apiculate. 



Sandy soil at Alameda and near Santa Cruz. 



4. C. douglasii Benth. Erect, with slender diffuse branches from the base 

 or more commonly simple below, 3 to 10 in. high, pubescent throughout; rad- 

 ical leaves oblanceolate; cauline similar but reduced above, 3 to 6 lines long; 

 involucres in small loose clusters, each \\U lines long, densely hairy in the 



