

316 POLYGONACE.E. (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 broadly 

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

 glabrous. Colorado. 



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

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

 brate above: involucres narrower and rather moreflrm, shortly toothed, somewhat 

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

 Mountains. 



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

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

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

 braska to Colorado. 



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



cyme. 



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

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

 usually narrow, revolute, becoming glabrate above : involucres often peduncu- 

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

 Nevada, and Oregon. 



Var. effusum, 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 E. 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 white-tomentose base : leaves linear to narrowly 

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

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



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

 twice forked panicle. 



27. E. racemosum, 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 



