BUCKWHEAT FAMILY. 161 



Ponds and lakes in the mountains of the Coast Ranges and Sierra 

 Nevada and also in sloughs of the interior valleys. 



8. P. Muhlenbergii "Wats. Perennial, aquatic or in half dry 



E laces; leaves and upper portion of the simple stem appressed- 

 irsutulose or scabrous, the peduncle glandular with short hairs; 

 leaves thin, ovate-lanceolate to lanceolate, acuminate or even atten- 

 uate, usually rounded at base, 3 to 8 in. long, the petioles 1 to 3J in. 

 long; spikes 1 to 3 in. long, often in pairs; calyx rose-color or pink, 

 5-partea to -the middle; stamens 5, exserted; style 2-cleft; achene 

 lenticular. 



Mountain Lake, San Francisco; Healdsburg, Alice King; ranging 

 to the interior (sloughs of the Lower Sacramento, Jepson). June- 

 Oct. 



9. P. Hartwrightii Gray. Perennial; closely allied to F, 

 amphibium but differing in its rough hairy sheaths, which are 

 ciliate and usually with an abruptly spreading herbaceous margin; 

 leaves mostly narrow, either lanceolate or oblong, 2 to 7 in. long, on 

 very short petioles, arising from the middle of the sheath. 



Sierras; va the Bay Region, ace. to Greene. 



10. P. lapathifolium L. Common Knotwbed. Annual, com- 

 monly stout, 1 to 4 ft. high, branching, glabrous except a very scanty 

 glandular pubescence on the peduncles and a scabrous pubescence on 

 the leaf-margins; leaves broadly lanceolate, attenuate upward from 

 near the base and mostly long-acuminate, ouneate at base and short- 

 petioled, 4 to 5 in. long; spikes axillary and terminal, oblong and 

 erect or linear and nodding, 1 in. long or more; calyx white or flesh- 

 color, 1 line long; stamens 6, included; styles 2 or 3-parted; achene 

 lenticular or rarely triangular. — (P. nodosum Pers.) 



Common along streams or in low or marsh land, often whitening 

 great areas. Aug.-Sept. 



11. P. Persicaria L. Lady's Thumb. Resembling P. lapathi- 

 folium but the sheaths and bracts conspicuously ciliate; leaves sub- 

 sessile; spikes shorter and erect; stamens generally 6, included; style 



2 or 3-parted. 

 Rarely seen. 



12. P. punctatum Ell. Dotted Smart-weed. Perennial, root- 

 ing and decumbent at base, erect and branching above, 2 to 5 ft. high, 

 glabrous or the margin of the leaves scabrous; leaves lanceolate to 

 linear-lanceolate, acuminate, attenuate to a very short petiole, about 



3 in. long; sheaths and the short bracts bristly-ciliate; inflorescence a 

 panicle of spike-like racemes, these loose and filiform, 1 to 3 in. long, 

 erect on long peduncles; calyx greenish, conspicuously glandular, 

 5-parted, 1 line long; stamens 8, included; styles 2 or 3-parted to 

 the base; achene lenticular ot triangular. — (P. acre HBK.) 



Common in low and especially marshy ground or in moist mountain 

 meadows; Howell Mountain. Sept. 



13. P. Convolvulus L. Black Bindweed. Twining or trail- 

 ing, the stems 1 to several ft. long; herbage glabrous, pale green; 



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