ROSE AND STANDLEY—PLANTS FROM THE PINACATE REGION. 19 
lower leaves linear-oblanceolate, acutish, attenuate to the sessile base, 55 mm. long 
or less, dull yellowish green, sometimes whitened with a resinous excretion, the upper 
leaves smaller and linear, all glabrous, thick, very numerous; inflorescence corym- 
bosely much branched, the heads sessile or short-peduncled, 2 to 5 at the end of each 
branch, campanulate, 5 mm. high; bracts coriaceous, straw-colored, greenish at the 
tips, oblong to linear-lanceolate, the outer obtuse, the inner acute, all minutely 
ciliolate, otherwise glabrous, much imbricated; achenes 2 mm. long, strigillose, the 
tawny pappus 4 to 5 mm. long. 
Type in the U. S. National Herbarium, no. 574227, collected at the village of 
Sonoyta, Sonora, November 14, 1907, by Dr. D. T. MacDougal (no. 14). 
Although related to the more eastern Isocoma heterophylla, our plant may be dis- 
tinguished at once by its different inflorescence, more glabrous stem, and very different 
leaves. 
EXPLANATION OF PLATE 14.—a, Branch of the type specimen; b, head; c, floret and immature achene; 
d, involucral bract. a, Natural size; 6, scale 5; c, scale 10; d, scale 14. 
Pectis angustifolia Torr. Ann. Lyc. N. Y. 2: 214. 1828. 
Type locality, “‘On the Rocky Mountains.”’ 
MacDougal Crater, November 14, 1907, Sykes 27 (in part). 
Pectis papposa Harv. & Gray, Mem. Amer. Acad, II. 4: 62. 1849. 
Type locality, “California.” 
Pinacate Mountains, November, 1907, MacDougal; MacDougal Crater, November 14, 
1907, Sykes 27 (in part). 
Perityle emoryi Torr. in Emory, Mil. Reconn. 142. 1848. 
Type locality, ‘‘The Cordilleras of California.” 
Pinacate Mountains at 1200 meters, November 21, 1907, MacDougal 68. 
Porophyllum gracile Benth. Bot. Voy. Sulph. 29. 1844. 
Type locality, ‘‘Bay of Magdalena,’’ Lower California. 
The specimens collected apparently belong to this species, but they are in an 
unsatisfactory state for determination. 
Senecio filicifolius Greenm. ined. 
Walls Well, Ajo Mountains, Arizona, November 8, 1907, MacDougal 11. 
Sideranthus viridis Rose & Standley, sp. nov. PLATE 15. 
Biennial or perennial, somewhat woody near the base; stems slender, branched from 
the base and sparingly above, glabrous below, minutely glandular-viscid above, 
bright green; leaves linear and entire or sometimes with a few lateral lobes, bristle- 
tipped, bright green, finely glandular-viscid, small, rather numerous; heads numerous, 
solitary at the ends of the very slender, leafy branches; involucral bracts linear- 
lanceolate, irregularly imbricated, green for half their length, viscid, 5 or 6 mm. 
long; rays numerous, pale yellow, linear, 8 or 9 mm. long; pappus abundant, 
almost pure white; mature achenes not seen. 
Type in the U. S. National Herbarium, no. 574279, collected on the Pinacate Moun- 
tains, November 21, 1907, by Dr. D. T. MacDougal. 
This is easily separated from the other members of the genus by its bright green 
stems and leaves, the latter of peculiar form. The pubescence, too, is different from 
that of our other species. 
EXPLANATION OF PLATE 15.—a, Root and base of plant; b, branch of type; c, involucral bract; d, flower 
with young achene; e, leaf and axillary branch; f, ray floret. a, b, Natural size; c, d, scale 8; ¢,f, scale 4. 
Trixis californica Kellogg, Proc. Calif. Acad. 2: 182. /. 53. 1863. 
Type locality, ‘‘Cerros Island.” 
Quitovaquito, Sonora, November 11, 1907, MacDougal 16. This is the species that 
has been passing as Trizis angustifolia DC. That, however, is a very different plant, 
with leaves of different form and with strongly pubescent stems. 
