BLAKE. — ENCELIA AND RELATED GENERA. 351 



Herbs, with alternate linear leaves and four-angled achenes, or scapose, 

 with linear-lanceolate leaves (Helianthella) 



ENCELIOPSIS (Gray) A. Nels. {EncrUa, and o^is likeness).— 

 Heads large, many-flowered, radiate or discoid, the rays neutral; 

 flowers all yellow. Involucre hemispherical, the scales 2-3-seriate, 

 subequal or graduated with the outer shorter, lanceolate to lance- 

 ovate, equaling or somewhat exceeding the disk. Receptacle some- 

 what convex; pales soft and scarious, with abruptly narrowed hairy 

 tip, enfolding the achenes and falling with them. Rays long (1.5- 

 4.5 cm.) and narrow, several-nerved, pubescent on back and tube, 

 entire or tridenticulate, absent in one species; disk-corollas with 

 cylindric tube abruptly widened into the throat, and 5-toothed pubes- 

 cent limb. Anthers sagittate at base. St\'le-branches bluntish, 

 pubescent. Achenes of ray triquetrous, sterile, rarely maturing and 

 developing thin corky wings; of disk compressed, very flat, villous 

 particularly on the margins (or glabrate in one species), with blackish 

 body and white cartilaginous border passing above into 2 teeth or 

 awns, these connected by a fringe of short confluent squamellae, some- 

 times completely united into a thick entire crown. — Scapose xerophy- 

 tic perennials, with stout root and often much branched caudex, the 

 short branches bearing tufts of thick oval or rhombic 3-5-nerved 

 leaves, and one or several naked or 1-2-bracteate monocephalous 

 scapiform peduncles. Type species Encelia nudicaulis Gray. — -Four 

 species of very arid regions of the southwestern United States. 



Distinguished from Helianthella by the generally shorter squamellae, 

 from Encelia and Geraea by usual presence of squamellae, and from 

 all three by habit. Forming a connecting link between Geraea and 

 Helianthella, and probably having developed as an adaptation to 

 desert conditions of the mountain loving genus Helianthella. 



Helianthella § Enceliopsis Gray, Proc. Am. Acad. xix. 9 (1883), & 

 Syn. Fl. i. pt. 2. 283 (1884). 



Enceliopsis A. Nels. Bot. Gaz. xlvii. 432 (1909). 



* Heads discoid; plant hispid-canescent. 



1. E. NUTANS (Eastw.) A. Nels. Root tuberiform, becoming very 

 thick (3 cm.) and woody, bearing a short lignescent caudex from which 

 proceed the 1-5 scapes and the tuft of crowded leaves; leaves oval, 

 obtuse to rounded at tip, rounded at base, hispid-canescent with 

 appressed hairs, 2-5 cm. long, on margined petioles 2-6 cm. long; 

 scapes hispid with somewhat reflexed hairs, 1.5-2.5 dm. high, naked 

 or with one or two narrow bracts; heads nodding in fruit, 2-4 cm. 

 wide, 1.5-2 cm. high; scales densely hispid, lanceolate, 2-3-seriate, 



