Flora of New Zealand Series

R. longi-petiolatus Col. in T.N.Z.I. 25, 1893, 325.

Type locality: Poverty Bay. Type: Colenso, N.Z., No. 99, 1839. FL. 11-1. FT. 11-2.

Glab. succulent sparingly branched herb, up to ± 6 dm. long, creeping and rooting at nodes; stems long, fistulose, often floating in water; stock rather short, roots slender. Petioles of radical lvs 15-50 cm. long, narrowed to lamina and membr. sheath. Lamina ± reniform in outline 3-9 cm. diam.; 3-5-flabellately divided to or near base into broad- or narrow-obcuneate divisions; these again ± deeply cut or toothed. Cauline lvs 2-4, smaller. Peduncles simple or branched, lf-opposed, up to 15 cm. long; bracts narrow-lanceolate, up to 2 cm. long. Fls 1-2 cm. diam.; sepals 5, oblong, ± 4 mm. long; petals (3)-5-(7), narrow-oblong, us. ± 7 mm. long but sts much shorter, yellow; gland 1 basal. Fruiting heads globose to ovoid, 6-7 mm. long; achenes 1·5-2-(3) mm. long, obliquely ovoid, ± compressed to ± turgid, keeled; style ± 2 mm. long, slender, flattened and widened at base.

DIST.: N., S. Lowland slow-flowing streams, ponds, and wet ground from lat. 36° southwards.

Hooker (Fl. N.Z. 1, 1852, 10) says "petalis . . . sepalis 1/2 longioribus abbreviatisve", and adds "petals sometimes very small and almost wanting (as figured in the 'Icones Plantarum')". Colenso's longipetiolatus has sepals < petals; his specimens come from "watercourses, forests near South Norsewood, 1882". No detailed study of the whole group has been made.