262 PROCEEDINGS OF THE AMERICAN ACADEMY 



* * * Annuals (or n. 54 perennial), branching from the base, with leaves devel- 



oped at the nodes in tlie axils of ordinary triangular bracts : flowers minutely 

 glandular. — (§ Substipulata, Benth. Pseudo-stipulata, Torr. & Gray.) 



53. E. ANGULOSUM, Benth. Floccose-tomentose, the branches mostly 

 4-6 angled : lower leaves orbicular to oblong-ovate, the upper oblong 

 to oblanceolate : involucres hemispherical, very many-flowered : flowers 

 rose-colored or greenish, J line long ; outer sepals ovate, concave, the 

 inner longer, lanceolate. — California to Arizona and Utah. 



54. E. Greggii, Torr. & Gray. Apparently perennial, puberulent : 

 leaves spatulate, ciliate and somewhat villous, smooth above, acutish : 

 involucres turbinate-campanulate, many-flowered : flowers purplish, the 

 sepals ovate-oblong. — N. Leon, Mexico. 



55. E. DiVARiCATUM, Nutt. Low, greyish pubescent : branches 

 terete : leaves thickish, all rounded or the upper oblong, petiolulate : 

 involucres very small and few-flowered : flowers whitish ; sepals oblong, 

 nearly equal. — W. Wyoming and S. W. Colorado. 



* * * * Tall stout white-tomentose annuals, with leafy simple stems, naked 



above : inflorescence cymose : involucres turbinate-campanulate, shortly ped- 

 unculate : flowers white, nearly glabrous ; sepals very unequal, the outer ovate- 

 oblong or round-cordate. — (Sp. of § Corymbosa, Benth., Torr. & Gray.) 



56. E. ANNUUM, Nutt. Leaves narrowly oblanceolate or oblong, 

 attentiate to a short petiole, mostly flat : involucres densely white-to- 

 mentose : flowers |- to 1 line long ; outer sepals oblong-obovate. — 

 Colorado to W. Texas and Northern Mexico. 



57. E. MULTiFLORUM, Beuth. Leaves lanceolate, sessile and some- 

 what aiiricled at base, smoother above and margin undulate : involucres 

 smoother: flowers 1^ lines long; outer sepals rounded cordate. — 

 Arkansas, Louisiana, and Texas. 



§ 3. Involucres cylindric-turbinate, more or less strongly 5-6-nerved, and often 

 becoming costate or angled, with as many short erect teeth, sessile (rarely 

 some of tliem pedunculate) in heads or clusters, or scattered in cymes or along 

 virgate panicled branches, always erect, rather large (1 to 3 lines long) : 

 bracts ternate, connate at base, usually short, acute and more or less rigid 

 (sometimes more or less foliaceous) : flowers not attenuate at base : akenes 

 usually glabrous. Mostly perennials, sometimes woody and leafy, more or 

 less white-tomentose. — Oeegonium. 



* Outer sepals broad and somewhat cordate, the inner much narrower : ces- 



pitose densely toraentose perennials, with short closely branched caudex : 

 involucres in a single head or short cymose umbel on the naked peduncle: 

 ovary scabrous above. — (§ Heterosepala, Torr. & Gray, & sp. of § Vir- 

 GATA, Benth., Torr. & Gray.) 



58. E. OVALIFOLIUM, Nutt. Low, densely cespitose : leaves round 

 or rarely oblong : bracts very small : involucres in a single close head : 



