102 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. XL 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. i. 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. Jamesii. 



Perianth yellow ; styles hairy only at the base. 



Involucres 6-8 mm. long ; leaf-blades oblong to oblanceolate. 



4. E. Bakeri. 

 Involucres 9-10 mm. long ; leaf -blades suborbicular to oval. 



5. E. arcuatum. 

 III. FLAVA. 



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. flavum. 



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. u. E. croceum. 



Perianth cream-color. 



Perianth about 6 mm. long at maturity ; leaf-blades spatulate-oblong or elliptic, 



glabrous above at maturity. 12. E. subalpinum. 



Perianth about 8 mm. long at maturity ; leaf-blades oval or ovate, permanently 

 tomentose above. J 3- E. latum. 



