inflated; basal leaves with petioles rarely to 25 cm. long, simple, reniform, to 6 

 cm. long and 1 dm. broad, deeply 3-parted or -divided, the primary parts or 

 divisions lobed to parted or divided, the ultimate lobes obtuse or rounded, the 

 sinuses rounded, cordate at base, rounded at apex, the broad stipular leaf bases 

 5-10 mm. long; cauline leaves alternate, the bracts often oblanceolate and entire, 

 sessile; pedicels to 2 cm. long in flower, 1-3 cm. long in fruit; sepals 5, greenish- 

 yellow, spreading, ovate, 2-3 mm. long, 1.5-2 mm. broad, pilose or glabrous, 

 persisting later than the corolla; petals 5, light-yellow, obovate, 2-5 mm. long, 

 1-3 mm. broad; nectary scale glabrous with the margins prolonged along the 

 blade of the petal, sometimes 1 or both with a free flap at the tip or the scale 

 often completely surrounding the nectary; stamens 10 to 25; achenes 40 to 300 

 in a cylindroid head 3-10 mm. long and 2-6 mm. in diameter, obovoid, 0.8-1 

 mm. long, often with minute irregular transverse ridges in the central unthickened 

 portion of each face, the periphery of the pericarp at least somewhat corky- 

 thickened, the surface often with ridges or a circle of "pin-prick" depressions at 

 the inner margin of the thickened zone, glabrous, the marginal keel obscure, the 

 style and the achene beak almost lacking, not recurved; receptacle obovoid or 

 cylindroid, 1-2 mm. long in flower, 2.5—9 mm. long in fruit, pubescent or some- 

 times glabrous. 



Borders of lakes, streams and marshland, often thriving in brackish or alkaline 

 sites, in Okla. (Garvin, Grady, Johnston, Roger Mills, Comanche, Alfalfa and 

 Cimarron cos.), in s.e. and s. Tex. to the Panhandle (Donley Co.), N. M. (wide- 

 spread) and Ariz. (Navajo and Pinal cos.), Mar.-Sept.; from Wash, to N.E., 

 s. to Tex., La. and Ga. 



The acrid sap of this species is said to raise blisters on human skin. 



25. Ranunculus Gmelinii var. Hookeri (D.Don) L. Benson. 



Glabrous or hirsute perennial; roots slender but fleshy, 1 mm. thick; stems 

 reclining or sometimes floating, prostrate, rooting at nodes, usually 1-5 dm. long 

 and a little branched; leaves all cauline and alternate or basal present and long- 

 petioled; petioles 1-4 cm. long, the stipular leaf bases 3-6 cm. long; blades 

 pentagonal in outline, 1-2 cm. long, 1.5-2.5 cm. wide or rarely to 6 or 9 cm. 

 in diameter, deeply 3-parted or -divided with the divisions 2 or 3 times forked 

 or sometimes dissected into ribbonlike divisions, the blade when dissected not 

 triternately dissected as in the dissected leaves of R. flabellaris, proximally deeply 

 cordate and distally rounded; often as many as 50 flowers produced; pedicels 

 1-2.5 cm. long in flower, 2-4 cm. long in fruit, glabrous or appressed-pubescent; 

 sepals 5, yellowish-green, spreading, ovate to nearly orbicular, 2.5-6 mm. long, 

 1.5-5 mm. wide, glabrous or pubescent, usually thick, deciduous with or before 

 the corolla; petals 5, yellow, orbicular or obovate, 4-7 mm. long, 3-6 mm. wide; 

 nectary scale variable, its margins prolonged into flaps (the tips of which are 

 usually free from the petal and joined, thus the scale usually encircling the gland, 

 or sometimes the margins joined distally, glabrous); stamens 20 to 40, the ellipsoid 

 anthers 0.5-1 mm. long; achenes 50 to 70, in an ovoid head 5-7 mm. long and 

 4-6 mm. in diameter, flattened-obovoid, 1-1.5 mm. long, smooth, glabrous, the 

 keel not corky-thickened but the basal and ventral portions of the pericarp 

 callous-thickened, the broad and thin beak 0.6-0.8 mm. long and recurved; 

 receptacle ovoid to obovoid, 1-2 mm. long in flower, about 4 mm. long in fruit, 

 hairy. 



In mud and shallow water of lakes, streams and marshes, often attached and 

 floating, in N. M. (Rio Arriba, Colfax and Taos cos.), June-Sept.; Nfld. and 

 N.S. to Alas., s. to Me., la., Mich., Minn., N.D., N.M. and Nev. 



952 



