Gen. N. Amer. Pl. 2: 71. 1818.
Annuals, perennials, shrubs, or subshrubs; (base usually woody); not scapose; glabrous or pubescent. Stems usually erect, rarely ascending, unbranched or branched. Leaves cauline and, sometimes, basal; petiolate or sessile; basal rosulate, petiolate, blade margins entire, lyrately lobed or 1- or 2-pinnatifid; cauline blade (base sometimes auriculate or amplexicaul), margins entire or dentate to pinnatifid. Racemes considerably elongated in fruit. Fruiting pedicels horizontal, divaricate, or divaricate-ascending, slender. Flowers: sepals spreading to reflexed, oblong-linear or linear, lateral pair not saccate basally; petals usually yellow or whitish, rarely white or yellow-orange, obovate, orbicular, oblong, linear, filiform, or oblanceolate, claw distinctly differentiated from blade (claw glabrous or papillose); stamens (exserted), equal; filaments not dilated basally, (often papillose basally); anthers linear, (strongly spirally coiled after dehiscence); lateral nectar glands annular, median present or absent, confluent with lateral ones. Fruits long-stipitate, linear, often torulose, terete or latiseptate; valves each with prominent midvein, glabrous; replum rounded; septum complete; ovules 22–70 per ovary; style obsolete or distinct (to 1.7 mm); stigma capitate, entire. Seeds uniseriate, plump, not winged, usually oblong, rarely ovoid; seed coat (obscurely reticulate), slightly mucilaginous when wetted; cotyledons accumbent to incumbent. x = 14.
w, c United States.
Species 7 (7 in the flora).
Both R. C. Rollins (1993) and N. H. Holmgren (2005b) reported n = 12 and 2n = 24 for various species of Stanleya. However, those counts, all reported previously by Rollins (1939c), are erroneous; no species of the genus has numbers deviating from n = 14 or 28.
All species of Stanleya are well-defined, and interspecific hybridization has not yet been reported. One species, S. pinnata, is a hyperaccumulator of selenium and is a good indicator for the presence of this element in soils. Poisoning of livestock results from their feeding on large quantities of plants of this species.
|1||Cauline leaves sessile, blade bases auriculate to sagittate||> 2|
|1||Cauline leaves petiolate, blade bases not auriculate or sagittate||> 3|
|2||Annuals or biennials (without caudex); racemes dense; sepals 6-12 mm; petals linear to filiform, 0.5-1.5 mm wide, margins crisped; fruiting pedicels 10-20(-26) mm.||Stanleya confertiflora|
|2||Perennials (with caudex); racemes loose; sepals 12-18 mm; petals narrowly oblanceolate, 1-3 mm wide, margins usually erose, rarely subentire and crisped; fruiting pedicels 4-9(-12) mm.||Stanleya viridiflora|
|3||Basal leaf blades: surfaces densely tomentose; fruiting pedicels 11-22 mm; petals with glabrous claws; fruits flattened.||Stanleya tomentosa|
|3||Basal leaf blades: surfaces usually glabrous, rarely sparsely pubescent; fruiting pedicels 3-11(-15) mm; petals with pubescent claws (except S. elata); fruits terete or subterete||> 4|
|4||Cauline leaf blades: margins usually entire, rarely dentate proximally||> 5|
|4||Cauline leaf blades: margins often pinnatisect, pinnatifid, 2-pinnatifid, lyrate-pinnatifid, or runcinate||> 6|
|5||Petals linear, 0.3-1 mm wide, claws glabrous; ovules 46-70 per ovary; filaments 5-13 mm; Arizona, California, s, w Nevada.||Stanleya elata|
|5||Petals oblanceolate to oblong, 2-3 mm wide, claws pubescent; ovules 10-38 per ovary; filaments 11-28 mm; Colorado, Kansas, Nevada, sw Texas, Utah, Wyoming.||Stanleya pinnata|
|6||Biennials; petals orbicular to broadly obovate, (2.5-)3-6 mm wide; fruits suberect to ascending, slightly curved inward.||Stanleya albescens|
|6||Perennials; petals oblanceolate or oblong, 0.8-3 mm wide; fruits usually spreading or divaricate, rarely ascending, sometimes curved downward||> 7|
|7||Cauline leaf blades: margins sometimes 2-pinnatifid; sepals 6.5-10 mm; petals 5-12 mm; filaments glabrous basally; gynophores 4-11 mm; fruits torulose, tortuous.||Stanleya bipinnata|
|7||Cauline leaf blades: margins not 2-pinnatifid; sepals 9-16 mm; petals 10-20 mm; filaments pilose basally; gynophores 7-28 mm; fruits smooth, not tortuous.||Stanleya pinnata|