138 POLYGONEiE. 



23. P. Davisije, Brew, in Gray Proc. Am. Acad. viii. 399 (1872). 

 Somewhat decumbent, 1 ft. high, stout, leafy throughout, flextious and 

 branching, pubescent with short spreading hairs, or nearly glabrous, the 

 leaf-margins scabrous-ciliate : leaves 1—2 in. long, ovate or oblong, 

 acute or obtuse, cuneate or rounded at base, subsessile : fl. in small 

 axillary and terminal cymose clusters, much shorter than the leaves : 

 sepals yellowish or purplish green, II2 — 2 lines long, narrow at base, 

 shorter than the achene. — On barren slopes near the highest summits of 

 the Sierra,* from Alpine Co. northward. Aug.— Oct. 



* * * * Twining or climbing annuals ivith broad leaves andjiowers in loose 

 axillary panicles or racemes; sepals green with whitish margins, enlarg- 

 ing in fruit; stigmas 3, subsessile; achenes triquetrous.— 

 Genus Bildekdykia, Dumort. 



24. P. Convolvulus, Linn. Sp. PI. i. 364 (1753). Fagopyram carinalum, 

 Moench. Meth. 290 (1794) ; S. F. Gray, Nat. Arr. ii. 272 (1821). Bilder- 

 dykia Convolvulus, Dumort. Fl. Belg. Prodr. 18 (1827). Twining or trail- 

 ing, 1—2 ft. high, minutely scabrous : leaves 1—2 in. long, hastate- 

 cordate, acuminate : fl. in axillary interrupted racemes : fruiting perianth 

 1% — 2 lines long, equalling the somewhat opaque granulate-striate 

 achene. — A weed in cultivated lands ; native of Europe, not yet prevalent 

 in California, but already met with near Berkeley, and in the valley of 

 the Sacramento. July — Sept. 



2. RUMEX, Pliny (Dock. Sorrel). Coarse perennials (rarely 

 annual or biennial), with leafy stems, and cylindrical obliquely truncate 

 scarious stipules ; the small green or reddish perfect or unisexual flowers 

 fascicled or verticillate, forming panicled racemes. Perianth of 6 

 (rarely 4) nearly or quite distinct sepals ; the outer herbaceous, spread- 

 ing or reflexed ; inner larger, in some becoming greatly enlarged in 

 fruit, appressed to the 3- (or 2-) angled achene. Stamens 6 ; filaments 

 very short. Styles 3 (or 2) ; stigmas tufted. Embryo lateral, slender, 

 slightly curved.— The docks (Lapathum) and sorrels ( Acetosa) seem like 

 good natural genera. The retention of our native sorrel (Oxyria) as 

 distinct from Acelosa on account of its dimerous flowers and winged 

 fruit, appears to us a relic of the empiricism of a former century. 

 » Fl. perfect or polygamous; valves accrescent, often with a grain-like 



protuberance on the back; leaves elongated, never hastate, pinnately 

 many-veined; herbage scarcely acidulous (except in n. 9). — 

 Old genus Lapathum ; the Docks. 

 ¥- Valves small (2 lines, more or less), one or more of them grain-bearing. 



■M- Valves with slender awned teeth; herlmge pubescent or scabrous. 



1. E. OBTUSiFOLius, Linn. Sp. PI. i. 335 (1753) ; Moench, Meth. 356 

 (1794), under Lapathum, also S. F. Gray, Nat. Arr. ii. 274 (1821). Tall 



