BUCKWHEAT FAMILY 53 



( 2 ) Flowers in a long narrow spike-like 

 cluster ; leaves basal, ovate to lanceolate, 

 white-woolly below E. racemosum 



2. Flowers yellow, yellowish or cream-colored 



a. Flower involucres in dense heads or head-like 



clusters 



(1) Heads single on a leafless stalk 



x. Heads with leaf-like bracts beneath E. fldvum 



y. Heads with inconspicuous bracts 



(x) Flower stalks 1-2 cm. high; leaves 



3-5 mm. long E. acaule 



(y). Flower stalks 5-30 cm. high; leaves 

 5-30 mm. long 

 m. Leaves ovate to elliptic E. ovalif oliiun 



n. Leaves oblong to spatulate E. caespitosum 



(2) Heads in umbels or in forking cymes 



x. Heads in umbels, the latter sometimes 

 compound 

 (x) Leaves linear or narrowly oblanceo- 



late E. chrysocephahun 



(y) Leaves oblong, spatulate, obovate or 

 rounded 

 m. Calyx hairy ; leaves mostly spatulate, 



woolly E. Mvum 



n. Calyx smooth 



(m) Flower stalk with a ring of 



leaves near the middle E. heracleoides 



(n) Flower stalk without a median 



ring of leaves E. umbelldtum 



y Heads in 2-4- forked clusters 



(x) Calyx tapering into its stalk E. Bdkeri 



(y) Calyx abruptly passing into its stalk E.lachnogynum 



b. Flower involucres in open much-branched 



clusters 

 (1) Stems leafy, not inflated; leaves oblanceo- 

 late to spatulate 



(a) Stems bristly-hairy, perennial, 2-6 ft. 



high; achenes winged E. aldtum 



(b) Stems smooth, annual, 2-6 in. high ; 



achenes not winged E. salsuyiuosum 



