This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Ranunculus sceleratus L. Sp. Pl. 551. 1753. R. eremogenes Greene, Erythea 4: 121. 1896.
Stout, glabrous, or nearly so, 6'-2° high, freely branching, stem hollow, sometimes 1 1/4' thick. Basal leaves thick, 3-5-lobed, on long and broad petioles, the blade 1'-2' broad, reni-form or cordate, those of the stem petioled or the upper sessile, deeply lobed or divided, the lobes obtuse, cuneate-oblong or linear, several-toothed or entire; flowers yellow, numerous, 3"-4" broad, the petals about equalling the calyx; head of fruit oblong or cylindric, 4"-6" long; achenes 1/2" long, very numerous, merely apiculate.
In swamps and wet ditches, New Brunswick to Florida, abundant along the coast, and locally westward to North Dakota, Kansas and Nebraska, extending to Alberta, New Mexico and California, preferring saline or alkaline situations. Also in Europe and Asia. Ditch- or marsh-crowfoot. Biting- or cursed-crowfoot. Water-celery. Blister-wort. Consists of several races. April-Aug.
R. recurvatus Poir. in Lam. Encycl. 6: 125. 1804.
Erect, 6'-2° high, usually hirsute, branching. Leaves all petioled, broadly reniform, 2'-3' wide, deeply 3-cleft, the divisions broadly cuneate, acute, toothed and lobed; flowers light yellow, 4"-5" broad, the petals shorter than or equalling the reflexed calyx; head of fruit globose, 6" wide; achenes compressed, margined, tipped with a recurved hooked beak of one-half their length.
Ranunculus acris L. Sp. Pl. 554. 1753.
Erect, hairy, branched above, 2°-3° high; roots fibrous. Basal leaves tufted, petioled, 3-7-divided, the divisions sessile and cleft into numerous linear to obovate mainly acute lobes; upper leaves short-petioled and merely 3-parted, distant; flowers numerous, bright yellow, about 1' broad; petals twice or thrice the length of the spreading calyx, obovate; head of fruit globose, 6"-7" broad; achenes compressed, short-beaked.
In fields and meadows, Newfoundland to Virginia, British Columbia and Missouri. Bermuda. Naturalized from Europe. Stem sometimes nearly glabrous. Yellow gowan. Gold-knops. Butter-rose, -cresses or -daisy. Horse-gold. Bachelor's-buttons. Blister-plant. May-Sept.