Plcroslcijia. IMJLYGUNACl'LK. 39 



* * Involucr€.H cylindrical : bracts not foliaccoiis. 



24. C. corrugata, Torr. & Gray, 1. c. Somewhat villous-i)ul)esceiit and toraen- 

 tose, luucli hiauclicd from the base and ascending, 2 to 4 inches higli : leaves ovate, 

 tomentose beneath, half an inch long, on slender petioles : bracts subulate-setaceous, 

 small : involucres numerous, the tul)e 1 or 2 lines long, narrow and attenuate at 

 base, scarcely angled, strongly corrugated, bearing 3 foliaceous ovate-lanceolate 

 short-awned and uncinate loljcs, somewhat tomentose al)ove and rather longer than 

 the tul)e : flowers white, included, less than a line long and aljout ecjualling the 

 pedicel : segments oblong, equal, villous above : stamens G or 9 on the middle of 

 the tube. 



Near Fort Yuma {Gen. Thomas) and noitlnvard in the Colorado Valley, Palmer. 



25. C. Watsoni, Torr. & Gray, 1. c. Villous-pubescent and somewhat tomen- 

 tose, with si>readiug or ])rocumbent branches, 2 to 4 inches long : leaves narrowly 

 oblanceolate, an inch long or less, tomentose beneath : bracts subulate-setaceous, 

 short or somewhat elongated, rarely foliaceous : involucres clustered or solitary ; 

 tube narrow and scarcely angled, 2 to 2i lines long, obscurely corrugated; teeth 5, 

 uiHvjual, subulate and uncinate, the larger often foliaceous, 1 to G lines long: flower 

 yellow, at length slightly exserted, on a slender pedicel, a line long : segments 

 oblong, acute, slightly villous : stamens 9, at the throat, with very short filaments. 

 — Watson, I5ot. King Exp. 313, t. 34. 



On the Mohave River (Palmer) ; Northern Nevada, Torrcy, JVatson, Lemmon. 



8. LASTARRI^A, Uemy. 



Involucre none. Perianth involucre-like, coriaceous or chartacef)us, tubular, 

 5 - G-cleft to the middle ; the narrow teeth rigid and awned, recurved and uncinate. 

 Stamens 3, inserted on the throat, with a small membranous tooth each side of the 

 very short iilament. Akene triangular, glabrous. Embryo curved ; the narrow 

 cotyledons longer than the radicle. — A small diffusely branching annual, native 

 of Chili, diffusely brancheil from the base and very fragile, with linear leaves, verti- 

 cillate oblong or lanceolate uncinately awned floral bracts, and floAvers sessile in the 

 forks and terminal. 



A single si)eeies, with the habit of Eachorizanthe. 



1. L. Chilensis, Kemy. ]>ranches ])rocumbent or ascending, 2 to 4 inches long, 

 hirsute : leaves an inch long or less, usually very narrow : lower bracts similar, in 

 whorls of 5 ; the floral ones U to 3 lines long, concealing the flowers : perianth 1 

 to 1.^ lines long, terete and becomimj chartaceous at base : styles very short. — Gay, 

 Fl. Chil. V. 289, t. 58, fig. 1; :Meisner in DC. Prodr. xiv. 18G ; Torr. & Gray, 

 Proc. Am. Acad. viii. 199. 



From Contra Costa County to San Diego ; poihaps introduced from Chili hy the agency of sheep 

 or cattle. It much rcsenil)lcs some species of Clii>riznnllir in appeamncc, and the flowers arc so 

 concealed by the bracts that the plant is liable to be overlooked. 



10. PTEROSTEGIA, Fisch. k Meyer. 

 Involucre of a single bract, subtending and shorter than tlie solitary sessile 

 flower, rounded and more or less 2-lobed, at length becoming enlarged, scarious and 

 reticulated, loosely enveloping the akene and gibbously 2-saccate on the back. Peri- 

 anth G- (rarely 5-) parted ; segments oblong-lanceolate, equal. Stamens inserted at 

 the base of the segments, as many or fewer. Akene triangular, glabrous. Cotyle- 

 dons rounded, accumbent upon the radicle. — Very slender weak leafy annuals, 



