gnaphaliacejE. 183 



* Involucral bracts few or none: receptacle chaffy. 



Fructiferous chaff or bract quite enclosing its achene; 



Achenes gibbous Gnaphalodes 21 



Achenes straight or curved; 



Receptacle columnar Ancistrocarphus 22 



Receptacle globular or ovoid Psilocabphus 28 



Fructiferous bract scarcely enclosing its achene; 



Receptacle columnar; pappuB none Ev AX 24 



Receptacle convex; pappus present Filago 25 



* * Involucral bracts many; receptacle not chaffy. 



Involucre dry, but hardly scarious Potohea 20 



Involucre herbaceous; achenes large .-. Adenocaulon 27 



Involucre scarions; achenes small Gnaphalitjm 26 



20. PLUCHEA, Cassini. Herb with alternate ample leaves, and a 

 terminal cymose cluster of smallish heads; these many-flowered, the 

 flowers largely pistillate only, their corolla reduced to a slender truncate 

 or 2 — 3-toothed tube, that of the hermaphrodite (but sterile) flowers 

 regularly 5-cleft. Achenes small, 4 — 5-angled or sulcate. Pappus a 

 series of capillary bristles. 



1. P. camphorata (L.), DO. Annual, stoutish, leafy, 2 ft. high; 

 minutely and somewhat viscidly pubescent: leaves oblong-ovate to 

 oblong-lanceolate, acute at both ends, toothed or denticulate, the larger 

 (3 — 5 in.) petioled: heads short-pedicelled, dull-purple, crowded in a 

 corymbiform cluster: involucral bracts ovate to lanceolate, often tinged 

 with the dull pale purple of the corollas. —Borders of brackish marshes 

 about Suisun Bay, etc. Aug. — Oct. 



21 GNAPHALODES, Tourn. Low floccose-woolly annuals, with 

 alternate entire leaves. Heads scattered, several-flowered. Pistillate 

 flowers on a small receptacle, each enclosed in a conduplicate bract, the 

 tip of which is scarious-appendiculate; the few hermaphrodite-sterile 

 ones mostly naked. Involucre outside of the fruiting bracts scanty and 

 scarious. Achene gibbous, obovate, enclosed in its bract and falling 

 away with it. Pappus none. 



1. G. Californica (P. & M.). Slender, erect, 6—12 in. high: leaves 

 mostly linear: fructiferous bracts. 5 or 6, firm-coriaceous, somewhat semi- 

 obcordate or semiobovate, straight anteriorly, the erect beak-like tip 

 largely scarious.— Open ground; very common. May. 



2. G. ainphibola (Gray). Fructiferous bracts about 10, somewhat 

 imbricated on an oblong receptacle, membranaceous or merely chartaceous 

 at maturity, the beak, an ovate almost hyaline appendage, at maturity 

 porrect— Hills of Contra Costa Co. May. 



22. ANCISTROCARPHUS, A. Gray. Low canescently flocculent 

 annual, erect, branched from the base, with alternate entire leaves, and 



