20 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Viguiera sp. 
Possibly V. deltoidea A. Gray. Papago Tanks, Pinacate Mountains, November 
17, 1907, MacDougal 50. The plants are not in flower and it is impossible to be cer- 
tain of their proper identification. 
Viguiera sonorae Rose & Standley, sp. nov. PLATE 16. 
Apparently a tall plant sparingly branched below; stems stout, finely and rather 
densely canescent throughout; leaf blades deltoid-ovate, thick, finely and densely 
canescent, obtuse, subcordate or truncate at the base, all on stout, finely canescent 
petioles one-third to one-half as long as the blade, the margins undulate, somewhat 
crispate; heads few, loosely corymbose, on peduncles 10 to 20 cm. long, naked or with 
a few much reduced leaves; heads subspherical, 15 mm. in diameter and 12 to 14 
mm. high; involucral bracts lanceolate, attenuate, finely and densely canescent; 
chaff of the receptacle oblong, entire or 3-toothed at the apex; achenes 8 mm. long, 
somewhat 3-angled, loosely and conspicuously pilose; pappus of 2 or 3 short, tri- 
angular-lanceolate palez at the angles of the achene and of several slightly shorter 
intermediate palex, the pappus finally deciduous, equaled or exceeded by the pilose 
hairs; rays about 2 cm. long, bright yellow. 
Type in the U. 8. National Herbarium, no. 574262, collected at the Papago Tanks, 
Sonora, November 20, 1908, by Dr. D. T. MacDougal (no. 57). 
Apparently this is not closely related to any other species. Its nearest relative, 
perhaps, is Viguiera canescens. 
EXPLANATION OF PLATE 16.—a, Part of type; 6, achene; c, palea of the receptacle; d, disk floret; ¢, involu- 
cral bract; f, ray floret. @, Natural size; b to e, scale 4; f, scale 2. 
