A. Gray

Smithsonian Contr. Knowl. 5(6): 11, plate 11. 1853.

Etymology: Greek drys, oak, and petalon, leaf, alluding to resemblance of petal shape to leaves of some oaks
Synonyms: Rollinsia Al-Shehbaz
Treatment appears in FNA Volume 7. Treatment on page 688. Mentioned on page 231, 232, 245, 246, 687, 693, 724.

Annuals or biennials; not scapose; usually pubescent or hirsute, rarely glabrous. Stems erect or ascending, unbranched or branched basally or distally. Leaves basal and cauline; petiolate or sessile; basal rosulate or not, petiolate, blade margins entire, dentate to runcinate, or pinnatifid; cauline petiolate or [sub]sessile, blade (base not auriculate, or auriculate to amplexicaul), margins entire or dentate to pinnatifid. Racemes (corymbose, initially congested), considerably elongated in fruit. Fruiting pedicels ascending, divaricate, or horizontal, slender. Flowers: sepals erect to ascending, oblong [ovate], lateral pair slightly saccate or not basally, (glabrous or pubescent); petals white or purplish, spatulate or obovate (longer than sepals), claw gradually narrowed from blade to base, (margins sometimes pinnatifid, or deeply 2-lobed); stamens tetradynamous; filaments not dilated basally, (glabrous or papillate basally); anthers oblong; nectar glands: lateral annular, median glands confluent with lateral. Fruits sessile or shortly stipitate, usually linear, rarely linear-oblong, torulose or smooth, terete or flattened (latiseptate); valves each with a distinct midvein, glabrous; replum rounded; septum complete, not veined; ovules 10–110 per ovary; style distinct; stigma capitate, usually entire, rarely slightly 2-lobed. Seeds uniseriate, plump, usually not winged, rarely narrowly so, ovate [oblong]; seed coat not mucilaginous when wetted; cotyledons accumbent [incumbent]. x = [10] 12, 14.


sw United States, n Mexico.


Species 8 (2 in the flora).


1 Cauline leaves shortly petiolate or sessile, blade bases not auriculate; fruits 0.5-1.2 mm wide; ovules 60-110 per ovary; seeds not winged; petal margins pinnatifid. Dryopetalon runcinatum
1 Cauline leaves sessile, blade bases auriculate; fruits 2-3 mm wide; ovules 10-28 per ovary; seeds winged (narrowly); petal margins usually entire, sometimes repand. Dryopetalon viereckii
... more about "Dryopetalon"
Ihsan A. Al-Shehbaz +
A. Gray +
sw United States +  and n Mexico. +
Greek drys, oak, and petalon, leaf, alluding to resemblance of petal shape to leaves of some oaks +
Smithsonian Contr. Knowl. +
al-shehbaz2007a +  and rollins1941a +
Rollinsia +
Dryopetalon +
Brassicaceae tribe Thelypodieae +