Rorippa palustris |
Rorippa dubia |
|||||
---|---|---|---|---|---|---|
bog yellow cress, common yellow-cress, hispid yellowcress, marsh cress, marsh yellow-cress |
|
|||||
Habit | Annuals or, rarely, perennials; (short-lived, terrestrial or of wet habitat, not submerged); usually glabrous, rarely hirsute, (trichomes cylindrical). | Annuals; usually glabrous, rarely sparsely pubescent. | ||||
Stems | (often simple from base), erect, branched distally, (0.5–)1–10(–14) dm, (sometimes hirsute proximally). |
(simple or branched from base), erect or ascending, branched proximally and distally, (0.4–)1.5–3.3(–4.5) dm, (glabrous or sparsely pubescent proximally). |
||||
Basal leaves | rosulate; blade [(4–)6–20(–30) cm × 10–50(–80) mm] margins lyrate-pinnatisect, (abaxial surface sometimes hirsute). |
not rosulate; blade margins pinnatifid. |
||||
Cauline leaves | petiolate or subsessile; blade lyrate-pinnatisect, (lateral lobes oblong or ovate when present), (1.5–)2.5–10(–18) cm × (5–)8–25(–30) mm, (lateral lobes smaller than terminal), base auriculate or amplexicaul, margins subentire or irregularly dentate, sinuate, serrate, or crenate, (abaxial surface sometimes hirsute). |
petiolate (to 4 cm) or (distal) sessile; blade lyrate-pinnatipartite or undivided, obovate, oblong, or lanceolate, (2–)3–11(–15) cm × (5–)10–30(–50) mm, (lateral lobes smaller than terminal), base auriculate or not, margins entire, irregularly crenate, or serrate (entire or serrulate distally). |
||||
Racemes | often considerably elongated. |
elongated. |
||||
Flowers | sepals erect, oblong, 1.5–2.4(–2.6) × 0.5–1 mm; petals yellow or pale yellow, spatulate, (1.5–)1.8–2.5(–3) × 0.5–1.5(–2) mm; median filaments 1–2.5 mm; anthers ovate, 0.3–0.5 mm. |
sepals erect, oblong-linear, (2–)2.5–3 × 0.5–0.7 mm; petals (usually absent), yellow, linear or narrowly oblanceolate, 1–1.5 × 0.2–0.7 mm, (shorter than sepals); median filaments 1.5–2.8 mm; anthers oblong, 0.5–0.8 mm. |
||||
Fruiting pedicels | divaricate or slightly to strongly reflexed, straight or curved, (2.5–)3–10(–14) mm. |
divaricate, straight, (2–)3–8(–10) mm. |
||||
Fruits | usually silicles, rarely siliques, often slightly curved, oblong, ellipsoid, or oblong-ovoid, (2.5–)4–10 × (1.5–)1.7–3(–3.5) mm; ovules 20–90 per ovary; style 0.2–1(–1.2) mm. |
siliques, straight, linear, (15–)25–40 × 0.7–0.9(–1) mm; ovules 70–90 per ovary; style 0.2–1(–1.5) mm, (stout, as thick as fruit). |
||||
Seeds | biseriate, brown to yellowish brown, ovoid or subglobose, 0.5–0.7(–0.9) mm (0.4–0.6(–0.7) mm diam.), colliculate. |
uniseriate, reddish brown, ovate-orbicular, 0.5–0.8 mm (0.4–0.6 mm diam.), foveolate. |
||||
2n | = 32, 48. |
|||||
Rorippa palustris |
Rorippa dubia |
|||||
Phenology | Flowering often year-round. | |||||
Habitat | Waste areas, slopes, roadsides, wet grounds, grassy places, field margins | |||||
Elevation | 0-500[-3700] m (0-1600[-12100] ft) | |||||
Distribution |
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NS; NT; ON; PE; QC; SK; YT; Europe; Asia [Introduced in n Mexico, South America, Australia]
|
LA; MS; OR; se Asia [Introduced in North America; introduced also in Central America, South America] |
||||
Discussion | Subspecies 2 (2 in the flora). Rorippa palustris is a highly variable species with controversial infraspecific taxonomy. B. Jonsell (1968) recognized four subspecies, of which one (subsp. palustris) is cosmopolitan and three are North American. R. L. Stuckey (1972) followed Jonsell but further divided the North American plants into eleven, poorly defined varieties. Division of the species into subspecies based solely on stem height and fruit length is artificial. The variation is continuous in every character, and the recognized infraspecific taxa represent only some of the extremes. Some collections cannot be adequately assigned to a given subspecies or variety, and of all the infraspecific taxa recognized, only two can be consistently separated from each other; they are recognized here as subspecies. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Rorippa dubia was treated by R. L. Stuckey (1972) as R. heterophylla and by R. C. Rollins (1993) as R. indica var. apetala. Both authors overlooked H. Hara’s (1955b) comprehensive account of its typification and that of R. indica. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||
Key |
|
|||||
Source | FNA vol. 7, p. 501. | FNA vol. 7, p. 500. | ||||
Parent taxa | Brassicaceae > tribe Cardamineae > Rorippa | Brassicaceae > tribe Cardamineae > Rorippa | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Sisymbrium amphibium var. palustre, Brachiolobos palustris, Cardamine palustris, Caroli-Gmelina palustris, Myagrum palustre, Nasturtium palustre, Radicula palustris | Sisymbrium dubium, Nasturtium heterophyllum, R. heterophylla, R. indica var. apetala | ||||
Name authority | (Linnaeus) Besser: Enum. Pl., 27. (1821) | (Persoon) H. Hara: J. Jap. Bot. 30: 196. (1955) | ||||
Web links |
|