652 



POLYGONACEAE. 



Vol. I. 



12. Eriogonum microthecum Nutt. Slen- 

 der Eriogonum. Fig. 1594. 



Eriogonum microthecum Nutt. Journ. Acad. Phila. 

 (II.) 1: 172. 1848. 



Perennial, woody, especially below, more or 

 less floccose-tomentose throughout ; stem erect or 

 ascending, branched, especially from the base, 

 leafy below, naked above, 6'-i2' high. Leaves 

 oblong or oblanceolate, obtuse at the apex, nar- 

 rowed into short petioles, ¥-2' long, the upper 

 bract-like ; inflorescence compoundly cymose ; 

 involucres top-shaped, ii" long, 5-toothed, the 

 teeth obtusish; bracts triangular; calyx white, 

 pink or reddish, i£" long, campanulate, at length 

 constricted near the middle ; stamens and style- 

 branches included ; achene pointed, 1" long, rough 

 on the angles. 



Western Nebraska to Washington, south to New 

 Mexico and California. July-Oct. 



13. Eriogonum effusum Nutt. Effuse 

 Eriogonum. Fig. 1^95. 



Eriogonum effusum Nutt. Journ. Acad. Phila. 



(II.) 1: 164. 1848. 

 Eriogonum microthecum effusum T. & G. Proc. 



Am. Acad. 8: 172. 1870. 



Perennial, shrubby, 6'-i6' high, white floc- 

 cose-tomentose ; stem stout, diffusely branched. 

 Leaves linear or narrowly oblong, ¥-i¥ long, 

 revolute; peduncles ¥-4' long, topped by 5-7 

 times compound stiff corymbose cymes; bracts 

 scale-like; involucres narrowly campanulate, 

 i"-ii" high, the tube slightly angled, the teeth 

 rather obtuse; calyx 1" high, white, glabrous, 

 the outer segments cuneate-obovate, rounded 

 at the apex, the inner notched ; filaments vil- 

 lous, especially below the middle ; achenes 

 3-angled. 



On dry plains or prairies, South Dakota and 

 Nebraska to Wyoming, south to New Mexico. 

 Summer. 



14. Eriogonum cernuum Nutt. Nodding 

 Eriogonum. Fig. 1596. 



E. cernuum Nutt. Journ. Acad. Phila. (II.) 1: 162. 

 1848. 



Annual, low, stem very short ; scape erect, usu- 

 ally much branched, 6-12' high. Leaves con- 

 fined to the short stem, orbicular or oblong- 

 orbicular, less than 1' long, obtuse or slightly 

 apiculate, flat, floccose-tomentose, especially be- 

 neath, petioled; inflorescence paniculate; involu- 

 cres campanulate, slightly more than ¥' long, 

 solitary on slender deflexed peduncles 1' long or 

 less, 5-cleft to near the middle, the lobes obtuse; 

 bracts triangular or lanceolate, not foliaceous; 

 calyx whitish, campanulate, i" long, 6-parted, 

 slightly constricted near the summit, the seg- 

 ments fiddle-shaped; stamens and style-branches 

 included; achene i" long, nearly globular at the 

 base, rough on the angles. 



Nebraska and Kansas to New Mexico and Utah. 

 July-Sept. 



Eriogonum Gordoni Benth., with the habit of E. cernuum; but with glabrous leaves, erect 

 slender peduncles and oblong calyx-segments, extends from Colorado into South Dakota. 



