316 POLYGON ACE^l. (BUCKWHEAT FAMILY.) 



* * Sepals similar and nearly equal : akenes smooth or nearly so. 



+- Involucres capitate, heads solitary : dwarf and cespitose, alpine or subalpine, 



densely white-tomentose. 



21. E. pauciflorum, Nutt. Caudex short-branched : tomentose through- 

 out, or the linear-oblanceolate revolute leaves glabrous above : involucres bruadhj 

 turbinate, nearly glabrous, thin, with broad somewhat scar ious teeth: flowers white, 

 glabrous. — Colorado. 



22. E. Chrysocephalum, Gray. Caudex more diffusely branched, 

 woody : tomentose throughout, the narrowly oblaneeolate leaves sometimes gla- 

 brate above : involucres narrower and rather more firm, shortly toothed, som> what 

 tomentose : flowers yellow, glabrous. — Proc. Am. Acad. xi. 101. Wahsatch 

 Mountains. 



23. E. multieeps, Nees. Rather diffusely branched at base, densely 

 white-tomentose throughout : leaves narrowly oblaneeolate : involucres rigid, 

 narrowly turbinate, with very short teeth: flowers rose-colored, pubescent. — Ne- 

 braska to Colorado. 



+- +- Involucres mostly solitary, in a repeatedly di- or trichotomous corymb-like 



cyme. 



24. E. microthecum, Xutt. Low and rather slender, woody and 

 diffusely much-branched, leafy below, more less white-tomentose : leaves 

 usually narrow, revolute, becoming glabrate above : involucres of ten peduncu- 

 late : inner sepals emarginate. — From Nebraska to New Mexico, the Sierra 

 Nevada, and Oregon. 



Var. eflfusum, Torr & Gray. With very diffuse and repeatedly divided 

 inflorescence. — More common eastward. 



25. E. corymbosum, Benth. Stouter and more rigid, usually densely 

 tomentose : leaves broader and less revolute : umbel stiff and broadly cymose : 

 involucres mostly sessile. — Including i?. microthecum, var. Fendlerianum, Benth. 

 Same range as last. 



26. E. brevicaule, Nutt. Less woody and more shortly branched at base, 

 glabrous or glabrate above the lohitc-tomcntose base: leaves linear to narrowly 

 oblaneeolate, attenuate to a very short petiole, often revolute, sometimes gla- 

 brate above : flowers yellow. — Idaho and Wyoming to New Mexico. 



+- +- +- Involucre sessile and solitary upon the few strict branches of the once or 

 twice forked pan ide. 



27. E. raeemOSUm, Nutt. White-tomentose, sparingly or not at all 

 branched at base, stout, 1 to 3 feet high : leaves large, ovate to oblong, on 

 long petioles : lower bracts somewhat foliaceous : involucres approximate, 

 tomentose : flowers white or rose-colored. — S. W. Colorado to Utah and 

 New Mexico. 



2. OXYTHECA, Nutt. 



Flowers, bracteoles, etc., as in Eriogonum. —Slender diffusely branched (re- 

 peatedly dichotomous) annuals, the slender internodes more or less covered 

 with small stipitate glands : leaves rosulate at the base : segments of the 

 glandular-pubescent perianth similar and equal. 



1. O. dendroidea, Nutt. A foot high or less, the scape-like stem 



