Ranunculus rionii Lagger

Wiegleb, Gerhard, Bobrov, Alexander A. & Zalewska-Gałosz, Joanna, 2017, A taxonomic account of Ranunculus section Batrachium (Ranunculaceae), Phytotaxa 319 (1), pp. 1-55 : 39-40

28. Ranunculus rionii Lagger , Flora (Regensburg) 31: 49 (1848).

≡ Batrachium rionii (Lagger) Nym., Bot. Not. 1852: 98 (1852).

Type : SWITZERLAND: In stagnis quibusdam circa Sedunum (Sitten), F. Lagger ( BM; isotype B, K, W etc.) .

Description

Annual, aquatic state spreading-erect with capillary leaves only (myriophyllid), terrestrial state caespitose with rigid capillary leaves. Shoots up to 50 cm long, green, glabrous, internodes of the middle part of the shoot as long as adjacent leaf. Laminar leaves absent. Intermediate leaves absent. Capillary leaves present, alternate, 20–30 mm long, obconical to suborbicular, green, glabrous, segments flaccid to subrigid, divergent, middle part shorter than the lateral ones, length between first and second bifurcation 3–10 mm, number of the lamina divisions 3–5(–6), number of final segments 150; petiole up to 20 mm long. Stipules for ca. 2/3 adnate to the petiole, glabrous, apex of free part rounded. Peduncles 30–50 mm long, 1 mm in diameter, curved, glabrous. Sepals 5, 2–2.5 mm long, lanceolate, greenish, spreading. Petals 5, 3.5–5 mm long, ovate to obovate, white with yellow claw, not contiguous during anthesis. Nectar pits 1 per petal, lunate, sometimes with terminal point. Stamens 10–25. Carpels (30–)60–90, 0.8–1.3 × 0.6–0.8 mm, subglobose, glabrous, style lateral or subterminal, 0.1–0.3 mm long, caducous. Receptacles subglobose, elongating to subulate shape in fruit, pubescent.—Chromosome number. 2n = 16.