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 abortivus L. Sp. Pl. 551. 1753.
R. abortivus encyclus Fernald, Rhodora 1: 52. 1899.
Glabrous, or but sparingly pubescent, 6'-2° high, branched. Basal leaves long-petioled, bright green, thick, crenate or sometimes lobed, broadly ovate, obtuse, and generally cordate or reniform, the cauline sessile or nearly so, divided into oblong or linear somewhat cuneate lobes; head of fruit globose, the receptacle short, pubescent; flowers yellow, 2"-3" broad, the petals oblong, shorter than the reflexed calyx; achenes tipped with a minute curved beak.
In woods and moist grounds, Labrador and Nova Scotia to Manitoba, south to Florida, Arkansas and Colorado. Recorded as biennial in duration. April-June.
Similar to the preceding species but usually smaller, villous with spreading hairs, flowering when very young, 6'-18' tall. Leaves thin, dull green, the basal ones ovate, obovate, or subor-bicular, 3-lobed or crenate, narrowed, rounded or subcordate at the base; segments of the upper leaves narrow, entire or sharply toothed; flowers yellow, about 3" broad; sepals narrowed into a short claw; petals oblong or oval, 2-3 times as long as wide; head of fruit rather longer than thick, the receptacle linear, glabrous or very nearly so.
In rich woods, often on rocks, Maine to Minnesota, Saskatchewan, Georgia, Arkansas and Colorado. In New York it blooms somewhat earlier than the preceding species. Roots tuberous. April-May.
Similar in aspect to R. abortivus and R. micranthus, glabrous, stem widely branched, 1°-2° tall. Basal leaves reniform or suborbicular, 6"-2' wide, long-petioled, crenate or some of them lobed, the teeth and lobes subacute; stem leaves sessile or the lower petioled, divided nearly or quite to the base into linear acute entire toothed or cleft segments; flowers 2"-3" broad; petals oblong, not exceeding the calyx, yellow, glandular; head of fruit globose or globose-oblong, 2" in diameter; achenes slightly compressed and margined, tipped with subulate hooked or recurved styles of about one-half their length.