: THISTLE FAMILY 923 



or elliptic, sulphur-yellow, glossy. Perhaps scarcely distinct from the preceding. 

 Geyser formations: n Wyo. Mont, Au-S. 



6. G. Williamsii Rydb. Probably biennial; stem 3-6 dm. high, branched 

 above, loosely floccose; leaves linear or Knear-laneeolate, decurrent, 5-10 cm. 

 long; inflorescence large, corymbosely paniculate; invohicre 6 mm. high, onlv 

 shghtly tomentose at the base; bracts broadly ovate, acute, light straw-colored 

 or white. Woods: Mont. MonL Au. 



7. G. microcephalum Nutt. Perennial, with a taproot; stem slender, 3-5 

 dm. high, simple below; leaves linear or the lower ob lanceolate, densely floccose; 

 inflorescence a narrow panicle; involucres campanulate, 4^5 mm. high; bracts 

 straw-colored to pearly-white, lance-ovate, acute. Along streams; Calif. — Ida. 

 • — B.C. 



8. G. Macounii Greene. Biennial, with a taproot; stem 5-8 dm. high, 

 corymbosely branched above, glandular-pubescent, loosely tomentose above; 

 leaves numerous, lanceolate to Knear, white-tomentose beneath, 5-10 cm. long; 

 heads numerous; involucres hemispheric, glabrous, about 5 mm. high; bracts 

 ovate or the inner lanceolate, all acute, white or straw-colored, turning rusty. 

 G. decurrens Ives, not L. G. Ivesii Nels. & Macbr. Open ground: N.S. — Pa. — 

 N.M.— Ariz.— B.C. PlainSubmont. Jl-S. 



9. G, palustre Nutt. A low spreading annual; stem at first erect, later 

 diffusely branched, with spreading branches, 5-20 cm, high; leaves 1-2 cm. long; 

 involucres 3-4 mm. high; bracts oblong to linear, brown, or the inner with white 

 tips. Wet places: Alta. — Neb. — N.M.—Calif. — B.C. Plain — SubmonL My- 

 Au. 



10. G. uliginosum L. Annual; stem at first simple, erect, later diffusely 

 branched, with ascending or spreading branches, 5-20 cm. long; leaves 2-4 cm, 

 long, 3-4 mm. wide; bracts oblong to linear, mostly acute, bro"v\Ti. Wet places: 

 Newf. — Va. — Colo. — Utah — Ore. — B.C.; n Eu. Plain — MonL Jl-Au. 



11. G. exilifolium A. Nels. Low annual; stem branching at the base; 

 branches decmnbent or adsurgent, 8-12 cm. long, sparingly floccose; leaves 2-4 

 cm. long; involucres about 3 mm. high; bracts lanceolate, acute, brown below, 

 white-tipped. G. angustifolium A. Nels., not Lam. Wet places: Colo. — Wyo. 

 Suhmont, — MonL Jl-S. 



12. G. Grayi Nels. & Macbr. Strict and simple annual; stem 1-3 dm. high, 

 appressed-tomentose; leaves all linear, appressed-tomentose, 1^ cm. long; invo- 

 lucres about 3 mm. long; bracts oblong to linear, wholly brown, or the innermost 

 with lighter tips, obtuse. G, stricium A. Gray, not Moench. Wet places; Wyo. 

 — N.M. — Ariz. Submont. — MonL Au-S. 



13. G. ustulatum Nutt. Perennial, with a short rootstock; stem 1-3 dm. 

 high, loosely floccose; leaves 2-8 cm. long, rather loosely floccose on both sides, 

 white beneath, greener above; glomerules of the heads arranged in a narrow 

 dense spike-like panicle; involucres about 5 mm. long; bracts ovate, abruptly 

 short-cuspidate, brown, shining. Closely related to G. purpureum of the At- 

 lantic States. In saline soil: B.C. — Mont. — Calif, Ap-Jl. 



58. ADENOCAULON Hook. 



Perennial herbs, with rootstocks. Leaves alternate, with winged petioles 

 and dilated blades. Inflorescence paniculate, the peduncles beset with stalked 

 glands. Heads many-flowered, discoid. Involucres turbinate of few thin 

 herbaceous bracts. Marginal flowers pistillate, 4-lobed or somewhat 2-lipi>ed. 

 Central flowers hermaphrodite, sterile, broadly funneKorm, deeply 4-5-cleft, all 

 white. Anther sagittate and the auricles minutely caudate. Achenes obovoid 

 or clavate, very obtuse, with stipitate glands above. Pappus none. 



1. A. bicolor Hook. Stem erect, 3-10 dm. high, more or less floccose; leaf- 

 blades deltoid-cordate, 5-10 cm. long, sinuate-dentate or somewhat lobed, soon 

 green and glabrate above, denselj^ white-tomentose beneath; involucres 2.5-3 

 -rr.m h\<rh fiirHinRfA: hra^ts 4 or 5. ovate, acute. reflexed in fruit: achenes 4-6, 



