328 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Stems erect; sepals with yellowish green edges. 

 Leaves oval or rounded, the upper ones not reduced . 12. P. achoreum. 

 Leaves oblong, the upper ones smaller than the lower ones. 



13. P. ramosissimum. 



1. Polygonum convolvulus L. Wild buckwheat. Occasional at low altitudes, in 

 waste ground or on open slopes. Native of Eur. ; widely naturalized in N. Amer. (Bil' 

 derdykia convolvulus Dum.) — Slender glabrous annual; leaves 2 to 6 cm. long, slender- 

 stalked, acute; flowers greenish white, in short loose racemes. 



2. Polygonum muhlenbergii(Meisn.) S.Wats. Water smartweed. East entrance, 

 about ponds on prairie. B. C. to Calif., Va., and Me. {Persicaria muhlenbergii Small.) — 

 Stout perennial, 30 to 70 cm. high, the stems rooting below; leaves lanceolate, 

 stalked, 5 to 15 cm. long; spikes 3 to 8 cm. long. 



3. Polygonum amphibium L. Collected in lake 'near Bel ton by Umbach. Alaska 

 to Calif., N. J., and Que. {Persicaria cocdnea Greene.) — Usually floating in water; 

 leaves oblong, slender-stalked, 3 to 10 cm. long; spikes 1 to 3 cm. long. 



4. Polygonum bistortoides Pursh. Bistort. Common in moist meadows above 

 timber line, rarely found in moist places at lower altitudes. B. C. to Calif., N. Mex., 

 and Mont. (Bistorta bistortoides Small.) — Perennial with thick rootstocks, 15 to 40 

 cm. high, glabrous; basal leaves long-stalked, oblong, 6 to 15 cm. long, pale on the 

 lower surface; spikes 1 to 5 cm. long; stamens projecting beyong the sepals. 



The flowers are showy but they do not last long. The plants usually grow among 

 grasses and sedges. The Blackfoot Indians used the roots in soups and stews. 



5. Polygonum viviparum L. Alpine bistort. Plate 49, A. Frequent above 

 timber line, in meadows and on rock slides; occasionally found in moist places at 

 middle altitudes. Alaska to N. Mex., N. H., and Greenl.; also in Eiu-. and Asia. 

 {Bistorta vivipara S. F. Gray.) — Plants glabrous, 10 to 15 cm. high; basal leaves oblong, 

 slender-stalked, 2 to 8 cm. long, obtuse; spikes 2 to 7 cm. long, the lower flowers re- 

 placed by small green bulblets. 



6. Polygonum austinae Greene. East entrance, in gravel along creek. Alta. to 

 Wyo. and Calif . — Annual, 5 to 15 cm. high, slender, branched from the base; leaves 

 5 to 15 mm. long, bright green; flowers green, mostly in the axils of the leaves; bracts 

 very small. 



7. Polygonum engelmannii Greene. Dry brushy hillside near Sun Camp. B. C. to 

 Colo. — Erect annual, 5 to 30 cm. high, densely branched from the base, very slender; 

 leaves 5 to 20 mm. long, the upper ones very small; sepals green, with whitish edges. 



8. Polygonum douglasii Greene. PVequent at low and middle altitudes, in woods 

 or on open or brushy slopes. B. C. to Calif., N. Mex., N. Y., and Vt.— Erect annual, 

 15 to 40 cm. high, slender; leaves 2 to 5 cm. long; sepals green, with white or pink 

 edges. 



9. Polygonum polygaloides Meisn. Frequent on the east slope at low altitudes, 

 on dry open hillsides. Wash, and Oreg. to Wyo. and Mont. — Erect annual, 4 to 12 

 cm. high, very slender; leaves linear, 1 to 2 cm. long; flowers 2 mm. long, white or 

 pinkish. 



10. Polygonum minimum S. Wats. Frequent at middle altitudes and sometimes 

 above timber line, on open slopes or in woods or thickets. B. C. to Calif., Colo., and 

 Mont.— Slender annual, 3 to 15 cm. high, usually branched, very leafy; leaves oval 

 or obovate, 5 to 15 mm. long, bright green; flowers 1.5 to 2 mm. long, the sepals green, 

 with pinkish edges. 



11. Polygonum aviculare L. Knotweed. Common at low altitudes, on dry 

 slopes or on prairie; often extending well up along the trails. Native of Eur. and 

 Asia; widely naturalized in N. Amer. —Plants bluish green, much branched, usually 

 prostrate but sometimes erect when young or when growing among other plants; 

 leaves oblong or lanceolate, 5 to 25 mm. long, obtuse; flowers 2 to 3 mm. long. 



