354 POLYGONACEAE (BUCKWHEAT FAMILY) 



attenuate, villous-canescent. Sandy woods and barrens, " s. Mo." to Fla. 

 and Tex. 



2. E. AllSni Wats. Perennial, erect ; leaves oblong, canescent-tomentose 

 beneath, flocculent or glabrate above, the lower rather abrupt at base ; inflores- 

 cence leafy ; sepals elliptical, yellow, nearly glabrous. Dry soil, mts. of W. 

 Va. and Va. 



2. OXYRIA Hill. MOUNTAIN SORKEL 



Outer sepals smaller and spreading, the inner broader and erect (but un- 

 changed) in fruit. Stamens 6. Stigmas 2, sessile, tufted. Achene lenticular, 

 thin, flat, much larger than the calyx, surrounded by a broad veiny wing. 

 Embryo straight, in center of the albumen, slender. Low alpine perennial, 

 with round-kidney-form and long-petioled leaves chiefly from the rootstock, 

 obliquely truncate sheaths, and small greenish to crimson flowers clustered in 

 panicled racemes on 'a stoutish 1-2-leaved stem. (Name from 6fo, sowr, from 

 the acid leaves.) 



1. 0. digyna (L.) Hill. Alpine regions of the White Mts., N. H., and far 

 northw. ; Rocky Mts. (Eu.) 



3. RtTMEX L. DOCK. SORREL 



Calyx of 6 sepals ; the 3 outer herbaceous, sometimes united at base, spread- 

 ing in fruit ; the 3 inner larger, somewhat colored (in fruit called valves') and 

 convergent over the 3-angled achene, veiny, often bearing a grain-like tubercle 

 on the back. Stamens 6. Styles 3 ; stigmas tufted. Embryo slightly curved, 

 lying along one side of the albumen, slender. Coarse herbs, with small and 

 homely (mostly green) flowers, which are crowded and commonly whorled in 

 panicled racemes; the petioles somewhat sheathing at base. (The ancient 

 Latin name ; of unknown etymology.) 



a. None of the leaves halberd- or arrow-shaped b. 

 b. Valves entire or denticulate, 8-27 mm. broad c. 

 c. Grains of fruiting calyx 0, or single and minute, not one third as 

 long as the valves. 



Valves very large, 15-27 mm. broad 1. R. venosus. 



Valves 4-7 mm. broad. 



Pedicels with tumid joints 2. R. PaUentia. 



Pedicels obscurely jointed 3. R. occidental^. 



c. Grains 1-3, well developed, mostly one half to three fourths as 



long as the valves d. 



d. Pedicels filiform, curved or flexuous e. 

 e. Leaves crisped on the margin. 



Grains chiefly plump and rounded at both ends . . . 5. R. crispus. 



Principal grains tapering at summit 6. R. elongatwa. 



6. Leaves flat /. 

 /. Pedicels with tumid joints, rarely exceeding the coriaceous 



greenish, straw-colored, or dull brown calyx. 

 Grains 3, 

 As broad as or broader than the wings of the valves . 7. R. pallidua. 



Narrower than the wings 8. R. mexicanus. 



Grain 1 9. R. altissimus. 



f. Pedicels obscurely jointed, mostly exceeding the membra- 

 nous finally purplish calyx. 



Grains 3 4. R. Britannica. 



Grain solitary 3. R. occidentalis. 



d. Pedicels clavate, deflexed, straightish and slightly rigid, 2-3 



times as long as the subacutninate valves . . . . 10. R. verticillatus. 

 6. Valves entire or nearly so, scarcely 2 mm. broad, grain-bearing . 11. R. eonglomeratus. 

 b. Valves with long sharp salient teeth at least near the base. 



Perennial; pedicels filiform, longer than the subherbaceous valves 12. R. obtusifolius. 

 Perennial : pedicels thick, shorter than the thickish indurated 



valves 13. R. pulcher. 



Annual ; teeth of the valves bristle-form 14. R. persicarioides. 



a. Some or all the leaves halberd- or arrow-shaped. 



Valves much exceeding the fruit ; leaves arrow-shaped . . .15. R. Acetosa. 

 Valves much exceeding the fruit; leaves halberd-shaped . . .16. R. hastatulws. 

 Fruit exserted from the minute scarcely changed calyx . . .17. R. Acetosella. 



