Physaria densiflora (A. Gray) O’Kane & Al–Shehbaz, denseflower bladderpod, low bladderpod. Annual, fine–taprooted, rosetted, 1—several–stemmed at base, erect or decumbent, in range to 15 cm tall; shoots with basal leaves and several cauline leaves, covered with appressed, sessile and subsessile scalelike hairs having mostly 5—7 rays (to 10 arms), with a U–shaped notch on one side, and minute bumps on upper surface (tuberculate).
Stems cylindric, < 1 mm diameter, green to reddish, with appressed, scalelike hairs.
Leaves helically alternate, pinnately lobed and petiolate (basal leaves) unlobed and sessile (cauline leaves), without stipules; petiole ascending, hemi–cylindric, to 10 mm long; blade obovate in outline to elliptic or oblanceolate, 6—30 × 2—6 mm, tapered at base, shallowly lobed to entire, acute at tip, pinnately veined with midrib slightly sunken on upper surface and slightly raised on lower surface, scalelike hairs evenly spaced.
Inflorescence raceme or panicle having also a lateral raceme arising axillary from the node below the terminal raceme, terminal, several–flowered, with open flower overtopping buds, without bracts, green tissues covered with appressed, scalelike hairs; peduncle and rachis increasing during fruit development; pedicel at anthesis 4—5 mm long increasing 2× in fruit.
Flower bisexual, ± radial, 7—8.5 mm across; sepals 4, lanceolate to elliptic, 2.8—3.8 × 1—1.2 mm, light yellow–green, inner pair with narrow membranous margins, covered with several–rayed appressed hairs; petals 4, lacking claw, obovate, 3.5—7 × 1.5—2.6 mm, bright yellow, pinnately veined, glabrous; stamens 6, free, mostly dimorphic, with 2 outer short and 4 of inner whorl longer; filaments 1.5—2.5 mm long (short stamens) and 1.8—4 mm long (long stamens), pale yellow; anthers dorsifixed (long stamens) and ± versatile (short stamens), dithecal, 1—1.2 mm long, yellow; pollen light yellow; nectaries at bases of stamens, minute, green; pistil 1, 3 mm long, not stalked; ovary superior, circular to elliptic in outline somewhat compressed side–to–side parallel to septum, ca. 1 × 1 × 0.7 mm, light green, glabrous, 2–chambered, each chamber with 4—8 ovules; style pale green; stigma capitate, at or above level of upper anthers.
Fruit siliqua (silicle) ± sessile, dehiscent by 2 valves, to 16–seeded, subspheroid but not inflated, ca. 4—5 mm, scarcely furrowed around septum; persistent style (beak) erect, 2.2—2.5 mm long.
Seed ellipsoid to 3–sided, 0.5—0.6 × 0.35—0.4 mm, orangish brown, with domed cells.
A. C. Gibson