COMPOSITAE (composite FAMILY^. 495 



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

 narrowly lanceolate, flat^ very acute, 3-neryed, 3-4 cm. Ippg, slightly fleshy, 

 glabrous, the margins minutely scabrous-serrulate: heads many, in p, 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-?ub|ulate,, only tardily exserted: 

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

 of alkaU and water than any other species of this range; Wyom;ng and Col- 

 orado. 



2. Chrysbthamnus 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 la^nceolate, acute, ob- 

 scurely 3-nerved, 2.5-4, cm. long, often twisted,' ;pQargins obscurely scabro- 

 ciliate: heads about 8 mm. high,' nimierous, in stort, 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-Ui^ear or ^lightly 

 enlarged upward. — ^In dry cafions and on the slopes in alkali-free so^l; Col- 

 orado and Wyoming. 



3. Chrysothamaus 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-rankedi the outer 

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

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

 dry hills and plains; Colorado to Utah and Montana. , . . , 



3a. Chrysothamnus ptunilus 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. , 



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

 leaves numerous, mostly l-S-neryed,^ narrowly to broadly linear, strongly 

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

 driest slopes; 'Colorado and Wyoming, . . 



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

 2-3 dm. high, green and glabrous, more or less balsamicf-visoid : leaves very 

 numerous on the bra,nches, 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. 

 I901.)v-Scarcely distinct from the preceding; Colorado and Utah. 



5. Clirysothamnus 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 

 compoimd 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. puhervlus (Eat.) Greene, 1. CiJ-r-Exceedingly abjmdant 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- 

 cjrmose cluster of heads: leaves linear or spatulate-linear, obtuse, plane, 2r-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 



