326 COMPOSI't^ PBiLOCAPHUs 



HESPEKEVAX 



P. tenellns Nutt. 1. c. Canescently tomentose throughout with fine 

 appressed wood which soon detaches from the stem : stems at length much 

 depressed and branched, 1-3 inches long: leaves spatulate, 3-6 lines long: 

 heads very numerous, 2-3 lines in diameter : achenes half-line long, obo- 

 vate-oblong. In low grounds, Washington to California. 



F< Oreganns Nutt. 1. c. Silky-lanate: stems erect, 2-6 inches high 

 branching from near the ground : leaves nearly linear, attenuate below, 4r- 

 6 lines long : heads numerous, 4-6 lines in diameter ; achenes oblong-cylin- 

 draceous. Low grounds and roadsides, Oregon and Washington. 



* * Leaves little, and those subtending the heads seldom at all nar- 

 rowed at base : herbage and especially the heads loosely floccose- woolly. 



P. elatior Gray Syn. Fl. i pt, 2, Supp. 443. P. Oregonus var. elatior Gray. 

 Erect and caulescent, or at length with spreading branches, 3-6 inches 

 high, robust: leaves lanceolate subspatulate-linear, 6-12 lines long: 

 heads 4-6 lines broad, very leafy-subtended, loosely arachnoid-wooley, the 

 wool of the fructiferous bracts shorter and mostly close : achenes cylin- 

 draceous. Low places, Willamette and Golnmbia river valleys. 



P. brevissimng Nutt. 1. c. Stems very short, mostly simple : leaves ob- 

 long or lanceolate, 2-5 lines long, seldom surpassing the leaves : heads sol- 

 itary or very few, very wooley: achenes cylindrical or slightly clavate, 

 "Plains of the Oregon" Nuitall to California. 



28 HESPEREVAX Gray Pac. R. Rep. iv 101, t. ii. 



LoT^r annuals with mostly opposite leaves and smalt heads of 

 inconspicuous flowers. Heads discoid, many-flowered ; the pis- 

 tillate flowers with filliform corolla in several series on a convex 

 villous and centrally elevated columnar receptacle, each subtend- 

 ed by an ovate barely concave chartaceous chaffy scale : herma- 

 phrodite but sterile flowers several on the apex of the columnar 

 receptacle involucrate by a whorl of 3-7 coriaceous open bracts. 

 Bracts of the involucre resembling the chaff of the receptacle. 

 Pappus none. 



H. brevifolia Greene Fl. Fr. 1027 Evax caulescena Gray in part. Floc- 

 cose-wooUy: stems 4-12 lines high, simple, or branching from the base 

 often depressed: leaves lanceolate, 4-6 lines long, tapering into a slender 

 petiole: heads inconspicuous, in sessile terminal or axillary clusters, 

 or solitary, a line or two long : chaffy scales of the receptacle, becoming 

 rigid, those subtending the sterile flowers thicker and woolly insiside 

 achenes obovate-oblong, with a narrowed base, straight, more or less com- 

 pressed _ parallel to the subtendind chaff, very smooth. Dry barren spots 

 m priaries, southwestern Oregon and California. 



Subtribe ii Gnaphaleas Less. Syn. 269. Heads discoid, heteroga- 

 mous or androgynous or diceciously homogamous; the hermaphro- 

 dite or staminate flowers when in the same head much fewer than 

 the pistillate ones; pistillate flowers with filiform tubular corolla 

 shorter than the style; the staminate flowers with style or style-bran- 

 ches mostly truncate, all usually with capillary pappus. Becepta- 

 cle without bracts or chaff. Bracts of the involucre numerous, more 

 or less scarious or wilh scarious and often colored or petaloid sum- 

 mits. Anthers with slender tails. 



