Sedum nuttallii Torrey & E. James, yellow stonecrop. Annual, ephemeral leaf succulent, taprooted (much–branched), not rosetted, several—many–stemmed at base, ascending to decumbent, < 10 cm tall; shoots with only spreading cauline leaves, foliage glabrous and ± glaucous.
Stems cylindric, to 3 mm diameter, initially pale green aging light brown and having vertical lines (files) of elongate cells, initially glaucous.
Leaves alternate (helically or not), simple, sessile with base somewhat clasping, without stipules; blade straight or slightly curved upward, oblong–cylindric to lanceoloid, (3.5—)5—9.6 × 1.5—2.6 mm, yellow–green to bluish green or with reddish tinge, appressed to stem at base (short–spurred), entire, obtuse at tip, venation obscure.
Inflorescence leafy cyme, terminal, 20—60+–flowered, with (1—)several ascending to spreading branches, branches forked or not, flowers sessile and formed on upper side of axis, bracteate but flower often separated by internode from bractlet, bractlets on lower side of axis lacking flowers and resembling leaves; lateral branches 30—70 mm long, with stemlike axis, axis pale and ± straw–colored; bractlet leaflike, oblong–cylindric to lanceolid, 5—8 mm long.
Flower bisexual, radial, ca. 7—8 mm across (including the longest sepal), horizontally oriented; sepals 5, helically alternate, unequal with the largest sepal resembling a bractlet, lanceoloid, (< 1—)2—4 mm long within a single flower, fleshy, pale yellowish green and glaucous, obtuse (the outermost sepal) to acute at tip; petals 5 in 1 whorl, spreading (initially erect), oblong with acute point (mucronate), (2—)3—4.9 × 1 mm, light yellow, broadly channeled with deeper dimple above midpoint just before fleshy point; stamens 10 in 2 whorls, outer whorl free and arising between petals, spreading, inner whorl opposite petals and fused to bases, ascending; filaments 2.5—2.9 mm long, light yellow; anthers basifixed, dithecal, ± 0.7 mm long, light yellow, longitudinally dehiscent (inner whorl dehiscing first); pollen light yellow; nectaries 5, between base of petal and ovary (opposite), stalked fan–shaped, ca. 0.4 × 0.3 mm, white, nectar–producing; pistils 5, erect becoming widely spreading in fruit; ovaries ± D–shaped and somewhat compressed side–to–side, 2 × 1 mm, light yellow, rounded on back, each 1–chambered with 10+ ovules; styles tapered from and indistinct from ovary, to 0.5 mm long, whitish at base and greenish yellow above; stigmas small, terminal, greenish yellow.
Fruits follicles, 5, widely spreading at ca. 30 ° and fused at base, each 10+–seeded, ovoid flattened side–to–side, 2.6—3 mm long, with groove on upper side and point at tip (spinose).
Seed obovoid, 0.35—0.4 × 0.2 mm, orange–brown with white hilum.
A. C. Gibson