1907] Hall. Compositae of Southern California. 167 



64. LASTHENIA Cass. 



Glabrous slightly succulent annuals. Leaves opposite, mostly 

 narrow and entire, sessile. Heads on slender peduncles terminat- 

 ing the branches. Involucral bracts 5 to 15, more or less united 

 into a hemispheric or campanulate toothed cup. Receptacle coni- 

 cal, covered with projecting points which bear the linear or linear- 

 oblong flattened achenes. Flowers yellow. Pappus, in ours, none. 



1. L. glabrata Coulter! Gray, Syn. Fl. i. pt. 2, 324 (1884). 

 L. Coulteri Greene, Bull. Calif. Acad. i. 192 (1885). 



Usually branching, 1.5 to 3 dm. high : leaves linear and entire 

 or sometimes the upper pair broadly lanceolate and toothed, con- 

 spicuously connate and sheath-like at base : peduncles erect, often 

 elongated : involucre broadly hemispheric, 5 to 7 mm. high : ligules 

 about 8 mm. long : achenes narrowly obovate, mostly with obtuse 

 edges, the surface sprinkled with yellow rough gland-like points. 



Common along borders of salt-marshes near the coast and on 

 inland alkali flats from San Diego to Santa Barbara and the San 

 Joaquin Valley. 



There has been an attempt to specifically separate L. Coulteri. 

 the southern form, from L. glabrata, of middle and northern 

 California, on the basis of achenial characters, but these char- 

 acters are inconstant. The achenes of the typical form are prob- 

 ably never "perfectly smooth" but, as viewed through the 

 microscope, are always more or less roughened with minute pa- 

 pillae resembling, except for size, the more conspicuous ones of 

 the variety. The papillae of the variety are, moreover, quite 

 variable. They are commonly globular or obtuse-cylindrical in 

 shape, but in specimens from the San Joaquin Valley (Davy, no. 

 2430) they are slender and acute with incurved tips. The surface 

 of the achenes from a single head varies in color from silvery 

 gray and shining to dull brown and lustreless, this range being 

 shown in specimens from near San Diego (Hall, no. 3956). The 

 achenes are usually more obtusely angled in the variety than in 

 the species but sometimes the angles are decidedly acute, as, for 

 example, in specimens collected in Ventura Co., Apr. 7, 1902, by 

 Davy. Since these achenial characters are thus shown to be in- 

 constant and since there is not the least difference between the 



