Suppl. Meth., 89. 1802.
Biennials or perennials; (stoloniferous or simple or several from caudex); not scapose; (often glaucous). Stems erect or decumbent, unbranched or branched distally. Leaves basal and cauline; petiolate or sessile; basal rosulate, petiolate, margins entire, denticulate, or dentate; cauline blade (base auriculate or subamplexicaul [sagittate]), margins entire or dentate. Racemes (corymbose, several-flowered), considerably elongated or congested in fruit. Fruiting pedicels horizontal or, rarely, ascending, slender. Flowers: sepals erect, oblong, or ovate [obovate]; petals white, pink, or purple, spatulate [obovate, oblanceolate, oblong, or, rarely, broadly linear], (longer than sepals), claw obscurely differentiated from blade, (apex obtuse or rounded); stamens slightly tetradynamous; filaments not dilated basally; anthers ovate [oblong], (apex obtuse); nectar glands lateral, 2 and subtending stamens, or 4 and 1 on each side of stamen. Fruits sessile, obcordate, obovate, obdeltate, elliptical, or oblong, smooth, strongly angustiseptate, (winged or not winged apically); valves each obscurely to prominently veined, strongly keeled; replum rounded; septum complete; ovules 4–14[–24] per ovary; style included in, or much exceeding, apical notch; stigma capitate. Seeds plump or slightly compressed, not winged, ovoid [oblong]; seed coat (longitudinally, minutely reticulate to nearly smooth), not mucilaginous when wetted; cotyledons accumbent. x = 7.
North America, Mexico, South America (Patagonia), Europe, Asia, n Africa.
Species ca. 80 (3 in the flora).
Previous North American accounts (e.g., E. B. Payson 1926; P. K. Holmgren 1971; R. C. Rollins 1993) treated species of Noccaea as members of Thlaspi. As discussed under the latter genus (see references there) and as shown by M. Koch and I. A. Al-Shehbaz (2004), Noccaea is definitely distinct from Thlaspi. Excellent comments on the biology, variability, and distribution of the North American taxa were given by Holmgren and are not repeated here.
|1||Petals not flaring between blade and claw, 2-2.8(-3.6) mm; styles (0.2-)0.3-0.5(-0.6) mm; sepals (1-)1.3-1.8(-2.2) mm.||Noccaea parviflora|
|1||Petals often flaring between blade and claw, 3-13 mm; styles (0.3-)0.6-4.2 mm; sepals 1.5-5.3 mm||> 2|
|2||Styles (0.3-)0.6-1 mm; fruits not winged apically; petals 3-5 mm; arctic Alaska, Yukon.||Noccaea arctica|
|2||Styles (0.4-)1.1-4.2 mm; fruits usually winged, rarely not winged apically; petals (3.4-) 4.2-13 mm; Pacific and Mountain states.||Noccaea fendleri|