ROBINSON AND GREENMAN. — GENUS POROPHYLLUM. 33 



3-nerved, slightly reticulated, 2 inches long, 2 to 2h lines broad, entire ; 

 marginal glands elliptical, usually 2 or 3 on each side and often one at 

 the end of each leaf : heads 6 to 8 lines long, 25-30-flovvered, rather 

 densely clustered in terminal flat-topped leafy cymose corymbs (2 or 3 

 inches in breadth); individual peduncles shorter than the heads: scales 

 of the cylindrical involucre 5, oblong, obtuse or rounded at the apex, 5 

 lines long, 1 to l.V lines broad, pale green, with a double line of dark 

 linear glands near the middle : flowers white. — P. Seemanni, Wats. 

 Proc. Am. Acad. xxiv. 57 ; Rraudegee, Zoe, i. 313 ; not Schz. Bip. — 

 Collected by Dr. Edward Palmer in crevices of exposed rocks in high 

 mountains near Guaymas, Sonora, 1887, no. 279 (distributed as P. 

 Seemannii., var.). According to Dr. Palmer's notes the plant is called 

 Maravilla by the Mexicans and used for headache. 



H- +- Mexican species with corolla more deeply cleft and more or less distinctly 

 bilabiate ; teeth lanceolate ; achenes 2| to 3-| lines in length. 



*+ Achenes long and slender, tapering at the ape.x, about 4 lines long. 



19. P. gracile, Benth. Leaves fleshy, subterete. — Bot. Sulph. 29. 



20. P. n. sp. ? aff. P. gracile. Leaves not fleshy, flat, very narrowly 

 lance-luiear, 1 to 2 inches long, a line or two broad, with regular margi- 

 nal glands : heads solitary, terminal on very short slender peduncles : 

 cylindrical involucre green, slender ; scales with purple border and glands. 

 — A tall slender, much branched leafy plant collected at Fronteras, 

 Sonora, by C. V. Hartman, altitude 4,550 feet, 25 September, 1890, no. 8. 



*-*■ +H- Achenes shorter, 2 to 3 lines long : involucre very dark-purple, often 



pruinose-glaucous. 



= Spreading annuals : very likely a single species. 



2 1 . P. coloratum, DC. Prodr. v. 650. 



22. P. tagetoides, DC. 1. c. 



= = Perennials, a little shrubby at the base. 

 a. Involucral scales obovate, very broad and obtuse. 



23. P. filifolmm, Gray, Proc. Am. Acad, xviii. 107, xix. 35. 



6. Involucral scales narrower, oblong. 



24. P. Linaria, DC. 1. c. 649. 



-!- -I- M- Lower Californian shrubs, with geniculate and much branched stems, 

 short subulate fleshy leaves, and short many-flowered heads : achenes only 

 \\ lines in length. 



25. P. crassifolium, Wats. Proc. Am. Acad. xxiv. 57. 



26. P. tridentatum, Benth. Bot. Sulph. 30. 



VOL. XXXII. — .3 



