378 POLYGONACEAE 



Leaves mostly narrow and lanceolate, jointed upon a short petiole adnate to the short sheath of 

 the scarious stipules; flowers in axillary clusters, the clusters either more or less sep- 

 arated or crowded into a terminal leafy spike; stamens mostly 8, the filaments or some 

 of them often dilated at base; achene triquetrous. Subgenus AVICULARIA. 

 Perennial and more or less suffrutescent. 



Leaves revolute; flowers several in a cluster, crowded at the ends of the branches. . . . 



11. P. paronychia. 

 Leaves plane; flowers 1 to 3 in each axil, less crowded. 



Leaves linear ; dry foothills 12. P. bolanderi. 



Leaves oblong or obovate ; alpine 13. P. shastense. 



Annuals. 



Plants prostrate ; branches leafy to the ends 14. P. aviculare. 



Plants erect or ascending. 



Flowers in axillary clusters; leaves little reduced upwards. 



Achenes dull 15. P. ramosissimum. 



Achenes shiny 16. P. minimum. 



Flowers in very loose spikes; leaves much reduced upwards; plants % to 1% 

 feet high. 



Flowers deflexed; achenes black, shining 17. P. douglasii. 



Flowers erect; achenes brownish, dull 18. P. spergulariaeforme. 



Flowers in dense terminal leafy spikes; plants % to 4 inches high. 



Flowers greenish white ; ' ' achene brown " 19. P. imbricatum. 



Flowers whitish or rose-color ; ' ' achene black " 20. P. watsonii. 



2. Flowers strictly solitary in the axils of the leaves or bracts. 



Internodes in ours very short and the branches spike-like ; stamens 8 ; achene triquetrous ; leaves 

 very narrow, not jointed to the lacerate stipule; ours slender wiry brittle annuals. 

 Subgenus DURA VIA. 

 Sheaths conspicuously lacerate. 



Stems flowering above the base; sheaths lacerate into more or less bristle-like seg- 

 ments 21. P. calif ornicum. 



Stems flowering from very base ; stipules cottony 22. P. parryi. 



Sheaths 2-parted, the segments sharply but shortly toothed 23. P. bidwelliae^ 



B. Leaves cordate. 



Flowers in loose panieled racemes; stamens 8; aehene triquetrous; twining plants. Subgenus 



BlLDERDYKIA 24. P. Convolvulus. 



1. P. bistortoid.es Pursh. Steins several from a thick horizontal rootstock, 

 1 to 214 feet high, the leaves mostly basal, those above reduced and bract- 

 like; leaves erect, oblong to linear-oblong, 4 to 8 inches long, the petioles half 

 to as long; raceme dense, spike-like, % to IMj inches long; flowers white, on 

 slender pedicels, 2 to 4 lines long. 



High wet meadows in the Sierra Nevada, San Bernardino Mts. and North 

 Coast Ranges. East to the Rocky Mts. and far northward. 



Locs. Mt. San Jacinto, Hall 2358; Hocketts Mdws., Tulare Co., Hall $ BabcocTc 5604; 

 Giant Forest (Eound Meadow was white with its flowers in June, 1900), Jepson 708; Twin 

 Lakes, Alpine Co., Hansen 315; Bear Valley, Nevada Co., Jepson; Goosenest Mt., Butler 

 969; Morgan, Tehama Co., Hall $ BabcocTc 4331; Sisson, Hall $ BabcocTc 4070; Shackelford 

 Canon, Chandler 1708; Modoc Co., M. S. Baker; Trinity Summit, Goddard 103; South Yollo 

 Bolly, Jepson; Snow Mt. (ace. Zoe, 4: 175) ; Sherwood Valley, Davy 5160. 



Eefs. POLYGONUM BISTORTOIDES Pursh, Fl. 1: 271 (1814), type loc. Weippe, Idaho, Capt. 

 Lewis; Piper, Contrib. TJ. S. Nat. Herb. 11: 230 (1906) ; Small, Monog. N. Am. Polygonum, 28, 

 pi. 1 (1895). P. bistorta Wats. Bot. Gal. 2: 14 (1880), not L. P. cephalophorum Greene, 

 Pitt. 5: 198 (1903), type loc. Mt. Conness, 3 Aug., 1890, Harford. P. bernardinum Greene, 

 1. c. 199, type loc. Bluff Lake, San Bernardino Mts., Parish. Bistorta leptophylla Greene, 

 Leaflets, 1: 20 (1904), type loc. high Sierra Nevada, Bolander. 



2. P. alpinum All. Stems stout, erect, 2 to 7 feet high, arising from a 

 fleshy rootstock, 1 to 2 inches in diameter ; herbage glabrous or nearly so ; 

 leaves ovate, acuminate, 3 to 6 inches long, the short petiole narrowly wing- 

 margined to the base ; panicles terminal, loose, nearly or quite leafless, 3 to 7 

 inches long; flowers white. 



Subalpine, Yosemite to Mt. Shasta and west to Marble Mt. 



Locs. Lake Tenaya, Hall $ BabcocTc 3635; Hetch-Hetchy, Jepson 3488; Silver Lake, 

 Hansen 314; Donner Lake, Heller 7123; Bear Valley, Nevada Co., Jepson; Klamath Range, 

 Jepson 2883. 



Refs. POLYGONUM ALPINUM All. Fl. Pedem. 2: 206, t. 68, fig. 1 (1785), type European; 



