554 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
HELIANTHEAE, 
Involucral scales boat-shaped, each more or less inclosing a 
ray akene. 
Akenes all laterally compressed.........--.-.-.--..-.. Manta (p. 575). 
Akenes not laterally compressed. 
Ray akenes turgid, or somewhat obcompressed. 
~ Involucre 4 or 5-sulcate; disk flower solitary ... HEMIZONELLA (p. 577). 
Involucre not sulcate; disk flowers several... ... Hemizonia (p. 577). 
Ray akenes obcompressed. 
Rays about 5; pappus none...........-.----- LAGOPHYLLA (p. 577). 
Rays 8 to 13; pappus capillary................ BLEPHARIPAPPUS (p. 578). 
Involucral scales not inclosing the outer akenes. 
Pappus present, of well-developed scales or awns. 
Scales of the pappus 12 to 20, thin, fringed.......-- PTILONELLA (p. 578). 
Scales of the pappus awn-like. 
Awn-like scales 2 or 4, retrorsely barbed ......- Bivens (p. 578). 
Awn-like scales 2, subulate..............-.... Corropsis (p. 579). 
Pappus wanting, or crown-like, or of short teeth. 
Receptacle elongate-cylindric............-.------- RupbBEcKIA (p. 579). 
Receptacle flat or convex. 
Rays pistillate and fertile. 
Pappus none............-.------------- BALSAMORHIZA (p. 580). 
Pappus a toothed crown.......-...------ Wreruia (p. 581). 
Rays neutral. 
Akenes flat and thin............22-2----- HELIANTHELLA (p. 582). 
Akenes prismatic...........-.-.-.---+--- HELIANTHUS (p. 582). 
HELENIEAE. 
Bracts of the involucre in two series; receptacle naked; pap- 
pus none. ..........------------- +--+ 22 e ee ee eee eee JAUMEA (p. 582). 
Bracts of the involucre in one series. 
Akenes linear, 4-angled. 
Bracts of the involucre united..............---.--- ERIOPHYLLUM (p. 583). 
Bracts of the involucre separate, linear. 
Heads radiate. 
Pappus scales thin, blunt; viscid perennial. Hutsea (p. 583). 
Pappus scales awn-like; annual ........-..- Ricropaprus (p. 583). 
Heads rayless, but marginal flowers enlarged; 
pappus scales blunt, hyaline. -.......-..---- CHAENACTIS (p. 583). 
Akenes obpyramidal. ° 
Receptacle bristly .........-.------------------- GAILLARDIA (p. 584), 
Receptacle naked. 
Akenes 4-5 angled; pappus scales 10 to 20 ...-. HyMENopapPus (p. 584). 
Akenes 8-10 ribbed; pappus scales 5 or 6.....-. HELENIUM (p. 584). 
ANTHEMIDEAE. 
Ray flowers present. 
Receptacle chaffy. 
Involucre narrow; rays short .........------------ + ACHILLEA (p. 584). 
Involucre broad; rays conspicuous.........--.-.--- ANTHEMIS (p. 585). 
Receptacle naked .........----------------+--+-+-+--- CHRYSANTHEMUM (p. 585). 
Ray flowers none. 
Receptacle conical .......-.----------------+----+--- MATRICARIA (p. 585). 
