Classification
 Nomenclature
Scientific Name:
Rorippa amphibia (L.) Besser, Enum. Pl. [Besser] 27 (1822)
Vernacular Name(s):
Marsh yellow cress; Tall yellow cress
 Description

Perennial rhizomatous herb. Stems erect, glabrous or finely hairy, 30–80 cm tall. Lvs ± glabrous, variable in shape, spathulate- oblanceolate, cuneate; margins toothed. Lower lvs petiolate, auriculate at base, deeply pinnatifid with lobes becoming shallower toward apex, 8–16 × 2–6–(7) cm. Upper lvs smaller, pinnatifid or toothed, sometimes linear; auricles becoming 0. Pedicels glabrous, erecto-patent to patent, sometimes deflexed at fruiting, (5)–7–10–(12) mm long. Sepals 2–3 × 1 mm. Petals bright yellow, 3–6 mm long. Silicle glabrous, elliptic to ovoid, 1.5–3–(4) × 0.6–1–(2) mm, but often not or poorly developed; valves veinless; style 1 mm long. Seeds reddish brown, c. 1 mm long, finely colliculate, in 2 rows per locule.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]

 Biostatus
Exotic
 Phenology

Flowering: Nov.–Feb.; Fruiting: Nov.–Feb.

 Bibliography
Besser, W.S.J.G. von 1822: Enumeratio Plantarum hucusque in Volhynia, Podolia, gub. Kiioviensi, Bessarabiia Cis-Tyraica et Circa Odessam Collectarum, Simul cum Observationibus in Primitas Florae Galiciae Austriacae. Wilna.