STANLEYA Nuttall, Gen. N. Am. Pl. 2: 71 1818.

Ihsan A. Al-Shehbaz

Tribe: Thelypodieae Prantl in Engler & Prantl, Nat. Pflanzenfam. III. 2: 155. 1891.

Name derivation: for Lord Edward Smith Stanley, 1775–1851, British and ornithologist and statesman.

Type species: Stanleya pinnatifida Nuttall, nom. illeg. (= S. pinnata (Pursh) Britton, based on Cleome pinnata Pursh).

     Herbs, annual or perennial, sometimes woody at base or subshrubs. Trichomes absent or simple. Multicellular glands absent. Stems simple or branched, erect or ascending. Basal leaves (if present) petiolate, rosulate, simple, entire or lyrately lobed to 1- or 2-pinnatifid; cauline leaves petiolate or sessile, sometimes auriculate or amplexicaul, entire or dentate to pinnatifid. Racemes many flowered, ebracteate, dense, elongated considerably in fruit; rachis straight; fruiting pedicels horizontal to divaricate-ascending, persistent. Sepals oblong to linear, free, caducous, spreading to reflexed, equal, lateral pair not saccate at base. Petals yellow or rarely white, erect at base with ascending or flaring blades, longer than sepals; blades ovate to elliptic or oblong to linear, obtuse to subacute at apex; claws strongly differentiated from blade, subequalling sepals, glabrous or papillose, expanded at base, unappendaged, entire. Stamens 6, exserted, equal; filaments wingless, unappendaged, often basally papillose, free; anthers linear, strongly coiled spirally after dehiscence, not apiculate. Nectar glands confluent and median present, or median absent and lateral annular. Ovules 22–62 per ovary; placentation parietal. Fruits dehiscent capsular siliques, linear, terete or latiseptate, not inflated, unsegmented; valves papery, with a conspicuous midvein, glabrous, not keeled, often torulose, wingless, unappendaged; gynophore (0.4–)1–2.8 cm; replum rounded, visible; septum complete, membranous, veinless; style obsolete or distinct and to 1.7 mm; stigma entire, unappendaged. Seeds uniseriate, wingless, oblong, plump; seed coat slightly mucilaginous when wetted; cotyledons accumbent to incumbent. x = 14.

     Seven species: W United States.

References: Lichvar (1983), Rollins (1939), Turner (2004).

1. Middle and upper cauline leaves sessile, auriculate to sagittate.

     2. Annual or biennial; raceme densely flowered; sepals 6–12 mm; fruiting pedicels

          1–2(–2.6) cm; petals blade linear to filiform, 0.5–1.5 mm wide, crisped.......... 3. S. confertiflora

     2. Perennial with with caudex; raceme loosely flowered; sepals 12–18 mm; fruiting

          pedicels 0.4–0.9(–1.2) cm; petal blade narrowly oblanceolate, 1–3 mm wide,

          erose or rarely subentire..................................................................................... 7. S. viridiflora

1. Middle and upper cauline leaves petiolate, neither auriculate nor sagittate.

     3. Leaves densely tomentose; fruiting pedicels 11–22 mm; petals claws glabrous;

          fruits flattened.................................................................................................... 6. S. tomentosa

     3. Leaves glabrous or sprasely pubescent; fruiting pedicels 3–11(–15) mm; petal claws

          pubescent (glabrous in S. elata); fruits terete or subterete.

          4. Leaves entire, rarely lower ones dentate.

               5. Seeds and ovules 46–70 per fruit; petal claws glabrous; filaments 5–13 mm;

                   petal blade linear, 0.3–1 mm wide; Arizona, S and W Nevada, California.......... 4. S. elata

               5. Seeds and ovules 10–34 per fruit; petal claws pubescent; filaments 11–28 mm;

                   petal blade oblanceolate or oblong, 2–3 mm wide; Colorado, Kansas, Nevada,

                   SW Texas, Utah, Wyoming.......................................................................... 5. S. pinnata

          4. At least lowermost leaves bipinnatifid, pinnatisect, pinnatifid, lyrate-pinnatifid,

               or runcinate.

               6. Biennial; petal blade orbicular to broadly obovate, (2.5–)3–6 mm wide;

                   fruits suberect to ascending, slightly curved inwards.................................... 1. S. albescens

               6. Perennial; petal blade oblong to oblanceolate, 0.8–3 mm wide; fruits spreading

                   to divaricate or rarely ascending, often curved downwards.

                   7. Fruits tortuose, torulose; at least some lowermost leaves bipinnatifid;

                        petals 5–12 mm, blade 1.7–5 mm; sepals 6.5–10 mm; filaments glabrous;

                        gynophore 4–11 mm............................................................................ 2. S. bipinnata

                   7. Fruits neither tortuose nor torulose; lowermost leaves not bipinnatifid;

                        petals 10–20 mm, blade 5–10 mm; sepals 9–16 mm; filaments basally pilose;

                        gynophore 7–28 mm............................................................................... 5. S. pinnata