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POLYGONACEAE. 
Involucres in simple or compound umbel-like or head-like clusters. 
Perianths hairy. III. Flava. 
Perianth glabrous. IV. Umbellata. 
Perianth without a stipe-like base. 
Ovaries and fruit pubescent; involucres few, capitate or subcymose. 
V. Lachnogyna. 
Ovaries and fruit glabrous or nearly so. 
Involucres in head-like or umbel-like clusters. 
Perianth-lobes very unequal. VI. Heterosepala. 
Perianth-lobes equal or nearly so. VII. Capitata. 
Involucres in open cymes. 
Cymes i-sided and spike-like. X. Virgata. 
Cymes dichotomous or trichotomous. 
Bracts scale-like. 
Involucres, except those in the forks of the inflorescence, sessile in 
the bractlets; the uppermost conglomerate. 
Perennial with a suffruticose caudex or shrubby. 
VIII. Corymbosa. 
Annuals, erect and strict. IX. Annua. 
Involucres all peduncled, never conglomerate. XI. Pedunculata. 
Bracts leaf-like. 
Primary cauline leaves scale-like, with a pair or a fascicle of well- 
developed secondary leaves in their axils. XII. Divaricata. 
Primary cauline leaves well developed, often also with secondary 
leaves in their axils. XIII. Foliosa. 
I. Alata. 
Involucres hairy, when mature 3-3.5 mm. long and 1.5-2 mm. wide; stem and 
leaves manifestly hairy. 1. E. alatum. 
Involucres glabrous, when mature 2-2.5 mm. long and of the same width ; stem 
and leaves nearly glabrous. 2. E. triste. 
II. Eriantha. 
Perianth whitish ; styles hairy at least to the middle. 3. E. 
Perianth yellow; styles hairy only at the base. 
Involucres 6-8 mm. long; leaf-blades oblong to oblanceolate. 
4. E. 
Involucres 9-10 mm. long; leaf-blades suborbicular to oval. 
5- E. 
III. Flava. 
Jamesii. 
Bakeri. 
arcuatum. 
Stipe-like base of the perianth very short; old leaf-bases permanently tomentose. 
Leaf-bases thickened; perianth copiously white-pubescent; leaf-blades silky 
above; involucres usually several. 6. E. Havum. 
Leaf-bases not thickened; perianth sparingly pubescent; leaf-blades slightly 
floccose above; involucres 1-3. 7. E. aureum. 
Stipe-like base of the perianth slender; old leaf-bases glabrous. 
8. E. xanthum. 
IV. Umbellata. 
Perianth deep yellow. 
Umbels simple. 
Leaves densely tomentose beneath. 9. E. umbellatum. 
Leaves almost glabrous at maturity. 10. E. umbelliferum. 
Umbels compound; leaves tomentose beneath. 11. E. croceum. 
Perianth cream-color. 
Perianth about 6 mm. long at maturity; leaf-blades spatulate-oblong or elliptic, 
glabrous above at maturity. 12. E. subalpinam. 
Perianth about 8 mm. long at maturity; leaf-blades oval or ovate, permanently 
tomentose above. 13- E. latum. 
