Ranunculus ranceorum

Detailed description

Annual or short-lived perennial herb of lake shore marginal turf communities, forming diminutive rosettes up to 40 mm diam. Rarely solitary, frequently forming crowded patches comprising numerous smaller daughter offsets and seedlings. Rootstock stout, 2-4 mm diam., ascending, ± cylindrical, white, fleshy to succulent, apex covered with rotted, fibrous petiolar remnants, deeply and firmly rooted, branching at surface to form 1 or more rosettes. Petiole (5-)10(-20) mm long, fleshy to succulent, bronze green to bright green in exposed portion otherwise white, base grooved and broadly sheathing, otherwise weakly concave to flat or slightly convex on upper surface, margins usually bearing sparse, scattered, white, cobwebby hairs. Adult leaves (2.5-)9.0(-12.0) × (2.0-)7.0(-10.8), bright green, bronze green to dark green or dark green with brown veins, ± glossy, fleshy, broadly rhomboid, deltoid, to broadly ovate, lamina entire in seedlings and in initial emergent adult growth, otherwise 3-lobed to almost 3-foliate; lobe segments broad, concave, mostly entire, margins often finely though sparsely cobwebby hairy, glabrate. Peduncles initially sessile (sometimes remaining that way), or very short, up to 6 mm long, usually elongating slightly on fruiting, fleshy, ± succulent, up to 0.9 mm diam., white to green, glabrescent, bearing 2-4(-6) narrowly to broadly deltoid, entire, bracts. Flowers 2.5-7.0 mm diam., usually solitary or in scarcely separated pairst; sepals 5, caducous, 1.5-1.8(-2.0) mm long, green to greenish-white, broadly ovate to orbicular; petals 5 or absent, 0.8-1.3 mm, glossy yellow at apex only, ovate to almost spathulate, apex broadly obtuse to rounded; nectary 1, at base of petal, covered by an ovate scale, obscured by carpels; stamens 6-15; receptacle glabrous. Achenes 8-20, body 0.6-1.2 mm long, pale cream-brown, oblong to obovoid, convex on ventral and dorsal sides, cuneate at base; in cross section broadly ellipsoid; ventral margin rounded in upper 2/3 ± flattened to flat in basal 1/3, without any obvious ridge; dorsal surface rounded, prominently ridged, ridge hyaline, tapering toward beak, thickening toward base; surface glossy when fresh, distinctly punctuate, otherwise bearing irregular somewhat diffuse patches of caducous hairs; beak 0.05-0.10(-0.15) mm long, straight, weakly curved or hooked toward ventral side, often withered to a short black tipped stub, laterally compressed.