156 



POLYGONACEAE (BUCKWHEAT TAMILY) 



Spike usually solitary, short and thick. 



Sheaths neither spreading at summit nor fringed. 



Leaves obtuse or subacute 



Leaves acute or acuminate . . > . 

 Sheaths spreading at summit and somewhat fringed 

 Spikes several or many, rarely few. 

 Sheaths cylindric, naked. 



Spikes erect; styles 2-parted; achene orbicular 

 Spikes drooping (at least at tip); style 2-parted; achene 

 ovoid. , 

 Calyx and style each parted to below the middle 

 Calyx and style each parted nearly to the base • 

 Sheaths cylindric, fringed with bristles. 

 Spikes erect. 



Achene lenticular or triangular; spike dense. 

 Achene smooth, broadly ovoid , . 

 Achene granular, narrowly ovoid .... 

 Achene triangular; spike slender,, open 

 Spike drooping; achene lenticular or triangular. 

 Achene dull and granular .... 

 Achene smooth and shining ..'... 

 AVICULARIA. — Mostly annuals, usually rather small, with nar- 

 row leaves; achene triangular 

 Plants prostrate-spreading ...,., 

 Plants erect. 



Flowers axillary throughout. 



Achenes conspicuously exserted . . • . 



Achenes included. 



Branched throughout, the branches spreading. 



Leaves from oblong to oval 



Leaves from oblong to linear 



Branched from the base. 

 Pedicels erect. 



Achene oblong ..,..,. 



Achene ovoid 



Pedicels deflexed. 

 Achene ovoid, 

 i Upper bracts small and subulate 



, Upper bracts foliaceous 



Achene oblong ....... 



Flowers in terminal bracteate spicate-racemes. 

 Styles evident. 



Raceme long and interrupted ..... 



Raceme very short, subcapitate. 



Bracts winged ....... 



Bracts not wingedi 



Styles wanting or nearly so 



BILDERDYKIA. — Annual or perennial, the stem herbaceous 

 and twining (Tiniarm). 

 Outer calyx-segments unchanged in fruit 

 Outer calyx-segments developing wings . . - , 



3. P. amphibium. 



4. P. emeTsum. 



G. P. HartwTightii. 



6. P. pennsylTanicom. 



7. P. lapathifolium, 



8. P. incarnatum. 



9. P. Persicaria. 



10. P. penicarioidei. 



11. P. hydropiperoides. 



12. P. Hydropiper, 



13. P. punctatum. 



14. P. aviculaie. 



15. P. ezsertiim. 



16. P. erectiun. 



17. P. ramosisiimniii. 



18. P. sawatcheose. 



19. P. tenue. 



20. P. DouglasU. 



21. P. montanum. 



22. P. Engebnannii. 



23. P. spergulariaefonne. 



24. P. polygalbidei. 



25. P. Watsonii. 



26. P. KeUoggU. 



27. P. Convolvulus. 



28. P. scandeos. 



1. Polygontim bistortoides Pursh, Fl. Am. Sept. 271. 1814. Herbaceous 

 perennial with thick creeping chaffy rootstock; stem 2-6 dm. high: leaves few, 

 glabrous or with a minute hispid pubescence beneath; the radical on long 

 petioles, oblong, oblong-lanceolate to linear, either acute or obtusish at both 

 ends; the cauline much reduced and sessile upon the sheath, the margin often 

 revolute: flowers rose-color to white, on slender pedicels, in very dense ovate 

 to oblong spikes, and usually long-pedunculate: stamens and styles exserted: 

 achenes smooth and shining. [P. Kladna (Greene) ; P. calophylla (Greene), 

 both imder Bistorta in Leaflets 1: 18 & 19. 1904.]— New Mexico to Montana 

 and far northward and westward. 



la. Polygonum bistortoides linearifoUum (Wats.) Small, Bull. Torr. Bot 

 Club 19: 252. 1892. , Slender reduced alpine form with leaves tending to 

 linear: raceme ovoid. [P. linearifolia (Greene), imder Bistorta, 1. c.]— Alpine; 

 same range. 



2. Polygonum viviparum L. Sp. PI. 360. 1753. Perennial from a short 

 corm-like rootstock: stems 1-2 dm. high: leaves glabrous or rarely hispidulous 

 beneath; the radical oblong or lanceolate, 2-8 cm. long, varying from acute to 

 subcordate at base; cauUne from narrowly lanceolate to linear revolute: flow- 

 ers rather small, nearly sessile in- linear spikes 2-5 cm. long, the lower flowers 

 ;xt least replaced by sessile bulblets about 2 mm. long. [P. scopuKna (Greene), 



