COMPOSITAE (COMPOSITE FAMILY) 495 



the leafy flowering branches white, glabrous and striate: leaves suberect, 

 narrowly lanceolate, flat, very acute, 3-nerved, 3-4 cm. long, slightly fleshy, 

 glabrous, the margins minutely scabrous-serrulate: heads many, in a terminal 

 cymose corymb; involucre only 6-8 mm. high; the bracts few, unequal, not in 

 vertical ranks, the inner thin, obtuse, the outer ones with acute herbaceous 

 tips: corollas deeply cleft: style-tips linear-subulate, only tardily exserted: 

 achenes linear, villous-hirsute. Wet banks of alkali creeks; more tolerant 

 of alkali and water than any other species of this range; Wyoming and Col- 

 orado. 



2. Chrysothamnus glaucus A. Nels. Bull. Torr. Bot. Club 25: 377. 1898. 

 A slender, sparingly branched shrub, 5-10 dm. high; the older branches gray 

 with a shreddy bark; the season's twigs somewhat fastigiate, leafy, glabrous 

 with whitish shiny bark: leaves suberect, narrowly lanceolate, acute, ob- 

 scurely 3-nerved, 2.5-4 cm. long, often twisted, margins obscurely scabro- 

 ciliate: heads about 8 mm. high, numerous, in short, compact, terminal, 

 rounded, cymose corymbs; bracts subcarinate, 5-ranked, 3-4 in each rank, 

 lanceolate, acute, the outer greenish, the inner thin, membranous, glabrous: 

 corollas 4, lobes linear-lanceolate, about half the length of the tube: style- 

 tips linear-subulate, tardily exserted: achenes silky, short-linear or slightly 

 enlarged upward. In dry canons and on the slopes in alkali-free soil; Col- 

 orado and Wyoming. 



3. Chrysothamnus pumilus Nutt. Trans. Am. Phil. Soc. 7: 323. 1841. 

 Numerous -erect branches slender, 1-3 dm. high, glabrous, very leafy, the 

 bark whitish: leaves 2-4 cm. long, glabrous, slightly glutinous, narrowly 

 linear, very acute, 3-nerved, often involute or occasionally somewhat twisted: 

 involucre 4-6 mm. high; the bracts not very distinctly 4-ranked, the outer 

 short, ovate-lanceolate, the inner oblong-linear, not acute, faintly carinate. 

 [C. leucocladus Greene, Pitt. 5: 59. 1902 (?).] A very abundant species on 

 dry hills and plains; Colorado to Utah and Montana. 



3a. Chrysothamnus pumilus acuminatus A. Nels. Bot. Gaz. 25: 375. 

 1899. A very narrow-leaved form, the leaves scarcely twisted, and the bracts 

 more acute or even acuminate. (C. filifolius Rydb. Bull. Torr. Bot. Club 

 28: 503. 1901.) Rare; Colorado. 



36. Chrysothamnus pumilus varus A. Nels. 1. c. Low and freely branched: 

 leaves numerous, mostly 1-3-nerved, narrowly to broadly linear, strongly 

 twisted throughout. (C. elegans Greene, Erythea 3: 93. 1894.) On the 

 driest slopes; Colorado and Wyoming. 



4. Chrysothamnus Greenei (Gray) Greene, Erythea 3: 94. 1894. Plant 

 2-3 dm. high, green and glabrous, more or less balsamic 1 - viscid : leaves very 

 numerous on the branches, filiform-acerose but flat and margins minutely 

 ciliolate-scabrous: heads numerous and fastigiate-cymose, 6-8 mm. high; 

 bracts of the subclavate involucre oblong, abruptly subulate-tipped or short 

 outermost mucronate, only about 3 in each vertical rank, these ranks com- 

 paratively indistinct. (C. scaparius Rydb. Bull. Torr. Bot. Club 28: 503. 

 1901.) Scarcely distinct from the preceding; Colorado and Utah. 



5. Chrysothamnus lanceolatus Nutt. 1. c. 324. Cinereous-puberulent, 2-4 

 dm. high; branches terete: leaves linear-lanceolate, 3-4 cm. long, mucronate, 

 3-nerved, with scabrous margins: heads 6-8-flowered, in clusters, forming a 

 compound fastigiate corymb; bracts of the involucre oval, obtuse, or abruptly 

 somewhat acute, loosely imbricated in 3-4 series, the innermost glabrous, 

 nearly the length of the disk: lobes of the corolla about half the length of the 

 tubular portion: branches of the style elongated; the appendages lanceolate, 

 acute. [C. puberulus (Eat.) Greene, 1. c.] Exceedingly abundant throughout 

 our range. 



6. Chrysothamnus Vaseyi (Gray) Greene, 1. c. 96. Only 1-2 dm. high, 

 somewhat balsamic-viscid but wholly glabrous, leafy up to the fastigiate- 

 cymose cluster of heads: leaves linear or spatulate-linear, obtuse, plane, 2-3 

 cm. long, with obscure midrib: involucre cylindraceous ; the bracts narrowly 

 oblong, firm-chartaceous, and all but the innermost with a thickened greenish 

 spot at the very obtuse apex: lobes of the corolla short-linear: style-appendages 



