MOXOPETALOUS EXOGENOUS PLANTS. 349 



paniculatcly branched ; leaves linear, elongated, entire, 

 with the margins revolute, the lowest ones opposite; scales 

 of the involucre lanceolate, acuminate ; chaff of the recep- 

 tacle 3-toothed ; 7'ai/s 12-18, showy. — Varies, with broader 

 leaves, and the disk at first yellow. Stem 2°-G° high; 

 leaves 3-6' long. 



H. HETEROPHYLLUS, Nutt. Hirsute or hipsid; stem 

 slender, mostly simple, naked above ; leaves opposite, thick, 

 entire ; the lower ones lanceolate or oblong, tapering into 

 a petiole; the others linear, remote ; scales of the involu- 

 cre lanceolate, acuminate, ciliate ; chaff of the receptacle 

 3-toothed, the middle tooth cuspidate ; rai/s 15-20, elon- 

 gated. Stem 2°-4° high; lowest leaves 2'-6'loDg; rays 

 1^' long. 



H. ATRORUBEXS, L. Hirsute or hispid ; stem sparingly 

 branched and somewhat naked above ; leaves opposite, 

 oval, serrate, the lowest large and long-petioled; the upper 

 small, sessile, distant ; scales of the involucre oval or ob- 

 long, obtuse ; chaff of the receptacle acute ; rays about 12 ; 

 achenia pubescent at the apex. Stem 2°-5° high ; lowest 

 leaves 4-6' long; lieacls rather small. 



H. TOMEXTOSUS. Stem 4°-8° high, stout, hirsute, 

 branching; leaves all alternate, or lowest ones oppo- 

 site, very rough above, tomentose beneath, slightly serrate, 

 lowest ones large, ovate, on short-winged petioles; the 

 upper ones oblong; heads l^vgQ] scales of the involucre 

 numerous, lanceolate, acuminate, villous, spreading ; rays 

 15-20. 



*** Perennial ; disk yellow; heads small; leaves narrow. 



H. LOXGiFOLius, Pursh. Stem. 3''-4°, slender, branching ; 

 leaves lanceolate, sessile, entire, opposite, lowest contract- 

 ing in slender petioles and serrate ; heads few ; rays small ; 

 scales of involucre ovate-lanceolate, as long as the disk. 

 Leaves 6'-8' long. Resembles an aquatic Coreopsis. 



