/ 



1892.] NATURAL SCIENCES OF PHILADELPHIA. 361 



Var. Nevadensis. 



Of middle height, but widely and paniculately branching, the 

 small heads solitary or glomerate at the ends of the branches; 

 leaves green and glabrate above, hoary-arachnoid beneath, the lobes 

 rigidly spiny ; bracts of involucre closely appressed except the 

 slender-spinose tips. At the eastern base of the Sierra Nevada, 

 California, near Truckee, etc., collected by the writer in 1883. 



Carduus Mohavensis. 



Stoutish, branching, 3 to 5 feet high, whitish throughout, with a 

 minute and close tomentum ; leaves of lanceolate outline, narrow 

 and with lobes not overlapping, beai'ing few and rigid spines, the 

 middle cauline decurrent on the stem for one-third their length, 

 and all except the very lowest manifestly decurrent ; heads few and 

 terminal, small, round-ovate ; ovate involucral bracts somewhat 

 arachnoid, tipped with spreading spine of their own length or 

 longer ; segments of the reddish corolla as long as the throat ; 

 anther tips attenuate-subulate; pappus of marginal achenes merely 

 scabrous, of the others only sparsely plumose and that near the 

 base. 



At Rabbit Springs, in the Mohave Desert, 1886, S. B, Parish, n. 

 1,834; distributed as C. undulatus, from which its conspicuously 

 decurrent foliage and different pappus at once distinguish it. 



Carduus Rusbyi. 



Probably very tall, rather slender, paniculate above, with many 

 small ovate heads ; radical leaves long-petioled, 1 to 2 feet long, 4 

 inches wide, siiiuate-pinnatifid, only sparingly and rather softly 

 spinescent, pale beneath with a thin tomentum, glabrate above, in 

 texture quite thin ; floral leaves very small, each lobe and tooth 

 bearing a stout long spine ; ovate bracts of involucre appressed, 

 coriaceous, tipped with a long stout spreading spine ; flower appar- 

 ently whitish ; segments of the corolla little surpassing the throat ; 

 anther-tips attenuate ; outer achenes with scarcely barbellate bristles. 



Southern Arizona, 1883, Dr. H. H. Rusby. Sj^ecies remarkable 

 for the strong contrast between the soft and scarcely armed lower 

 leaves and the excessively spiuose floral ones. 

 Carduus Bernardinus. 



Rather slender, leafy below, bearing at summit 1 to 3 long pedun- 

 cled subglobose heads ; leaves of linear or lanceolate outline, sin- 

 uate-toothed or lobed, and with few small spines, equally white- 



