LAYiA COMPOSITE 351 



ACHYBACH^NA 



lar, perfect. Bracts of the involucre equal, in a single series, the 

 base convolute and enclosing the ray-achenes, foliaceous above, 

 Receptacle flat, pubescent, with a row of chaffy scales between the 

 ray and disk-flowers. Stjle^branches of the disk-flowers filiform 

 very acute, hairy above, at length exserted and recurved. Achenes 

 of the ray glabrous, linear-oblong, more or less obcompressed, 

 somewhat -incurved, crowned with a small protuberant areola, 

 destitute of pappus: of the disk linear^clavate, angled, appressed' 

 pubescent or villous, with a pappus of 10-20 equal bristles or 

 subulate awns which are naked and scabrous 'derrulat above and 

 plumose or villous with long weak hairs toward the base. 



Ii. glaudnlosa H. & A. 1. c. 358. Stems 4-12 inches hign, diffusely 

 branched, hispid or hirsute and with dark stipitute glands above: leaves 

 lineat-lanceolate, 1-2 inches long, the lower ones often more or less pinnati- 

 fld: heads solitary at the end of the branches, campanulate, 6 lines high ; 

 its bracts linear-oblong : rays 8-14, bright white, 6-8 lines long, 3-lobed : 

 chaff of the leceptacle lanceolate, equalling or exceeding the disk-flowers: 

 pappus 10-20 stout bristles, copiously villous. Sandy-banks and barren 

 grounds, Brit. Columbia to California and Idaho, east of the Cascade Mts. 



L. Vong^Iasii H. & A. 1. c. " Low, sparsely hirsute or hispid, a few 

 small stipitate glands on the upper leaves and involucre ; radical leaves pin- 

 natifid-dentate ; upper linear and entire: rays rather short, broad, 3- cleft: 

 lobes of disk-corollas hirsute outside : achenes narrow, those of the disk vill- 

 ous-pubescent : pappus of about 10 minutely scabrous linear-subulate flat 

 palese, nearly equalling disk-corollas; their rnargins toward the base scan 

 tily beset with long and straight villous hairs. Gravelly banks, between 

 the Dallee and Great Falls of the Columbia Eiver, Douglas." 



57 ACHYRACH.^NA Schauer, Del. gem. Hort- Vratsil 1838. 



A low annual with chiefly alternate leaves and middle-sized 

 heads of yellow flowers terminating the branches. Heads many- 

 flowered; the ray-flowers 6-10, with 3-cleft ligules much shorter 

 than its filiform tube, little surpassing the disk ; disk-corollas 

 slender, 5-toothed. Involucre oblong-campanulate, of lanceolate 

 thin-herbaceous bracts: chaff of the receptacle similar but thin- 

 ner, only between the disk- and ray-flowers, distinct. Achenes 

 all clavate, with attenuate base, symmetrical, 10-costate; those of 

 the ray slightly obcompressed, rounded at apex and with slightly 

 protuberant areola ; those of the disk mostly fertile, the truncate 

 apex bearing a large pappus of 10 elongated-oblong obtuse silvery 

 scarious palese, the 5 inner as long as the corolla and achene, the 

 alternate outer ones shorte. 



A. mollis Shauer 1. c. Villous-pubescent and slightly glandular- viscid : 

 stems erect, 6-18 inches high, branching: leaves alternate or the lowest 

 opjjosite, narrowly linear, 2-4 inches long, sessile, entire, or the lowest la- 

 ciniate: heads solitary, long-peduncled, terminating the stem and fastigiate 

 branches, an inch or less long : pappus 3 lines long, in fruit when dry 

 spreading and forming a globular silvery-chaffy head. Infields and open 

 places, southern Oregon and western California, 



Tribe v, HELENIOIDE^ B. & H. Gen. ii, 167. Heads hete- 

 rogamous and the ligulate ray flowers mostly fertile, or homogamous; 



