LAYIA COMPOSITE 351 



ACHYRACHJSNA 



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

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

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

 ray- and disk-flowers. Style-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 s des- 

 titute of pappus: of the disk linear-clavate, angled, appressed- 

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

 subulate awns which are naked and scabrous-serrulate above 

 and plumose or villous with long weak hairs toward the base. 



L. glandulosa H. & A. 1. c. 358. Stems 4-12 inches high, diffusely 

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

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

 fid : 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 receptacle lanceolate, equalling or exceeding the disk-flowers: 

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

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



L. Donglasii 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-corola hirsute outside : akenes narrow, those of the disk vill- 

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

 paleae, nearly equalling disk-corollas; their margins toward the base scan- 

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

 the Dalles and Great Falls of the Colnmbia River, Douglas. " 



57 ACHYRACH^ENA Schauer. Del. Sem. Hort. Vratsil 1838. 



A low annual with chiefly alternate leaves and middlesized 

 heads of yellow flowers terminating the branches. Heads many- 

 flowered; the ray-flowers 6-10, with 3-cleft ligule 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 

 theray 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 shorter. 



A. inollis Shaurer 1. c. Villous-pubescent and slightly glandular-viscid : 

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

 opposite, narrowly linear, 2-4 inches long, sessile, entire, or the lower la- 

 ciniate: heads solitary, long-ped uncled, 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. In fields and open 

 places, southern Oregon and western California. 



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

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



