Sedum laxum

(Britton) A. Berger

in H. G. A. Engler et al., Nat. Pflanzenfam. ed. 2, 18a: 451. 1930,.

Basionym: Gormania laxa Britton in N. L. Britton and J. N. Rose, New N. Amer. Crassul., 29. 1903
Treatment appears in FNA Volume 8. Treatment on page 218. Mentioned on page 201, 202, 217.

Herbs, perennial, cespitose or not, glabrous. Stems root-stocks, ascending, much-branched, bearing rosettes. Leaves alternate, erect to spreading, sessile; blade green, glaucous or not, not pruinose, oblanceolate, spatulate, or obovate, subterete or somewhat flattened, 10–50 × (4.5–)6–33 mm, base not spurred, not scarious, apex truncate to rounded or obtuse, emarginate or barely notched. Flowering shoots erect or decumbent, simple or branched, 4–30(–40) cm; leaf blades oblanceolate, spatulate, obovate, or suborbiculate, base not spurred; offsets not formed. Inflorescences elongate, paniculate cymes, 12–80-flowered, monochasially 3+-branched; branches not recurved, 2-forked; bracts similar to leaves, smaller. Pedicels 0.6–6.3 mm. Flowers 5-merous; sepals erect, (closely appressed to corolla tube), slightly connate basally, pale green, ovate or lanceolate, equal, (2–)2.6–5.1 × 2 mm, apex acute or subacute, (rarely obtuse in var. flavidum); petals basally erect, divergent in distal 1/2, connate basally, pink, pinkish white, or white to yellowish white, lanceolate-oblong, oblanceolate-oblong, or elliptic-oblong, not carinate, 4–11 mm, apex obtuse, shortly mucronate or aristate; filaments white, greenish white, or pink; anthers red, reddish purple, red-brown, or yellow; nectar scales white, yellow, or pink, reniform or transversely oblong. Carpels erect in fruit, distinct, brown.


Varieties 5 (5 in the flora).

Sedum laxum is unusual in forming offsets in axils of rosette leaves rather than on a rootstock or creeping stem.

Selected References



1 Flowering shoot leaf bases clasping stems. Sedum laxum var. heckneri
1 Flowering shoot leaf bases not clasping stems > 2
2 Petals pale yellow or white with pink mid- veins; sepal apices obtuse. Sedum laxum var. flavidum
2 Petals pink or white; sepal apices acute > 3
3 Flowering shoot leaf blades suborbiculate. Sedum laxum var. eastwoodiae
3 Flowering shoot leaf blades spatulate to oblanceolate > 4
4 Leaf blades 9-17 mm wide Sedum laxum var. laxum
4 Leaf blades 17-33 mm wide. Sedum laxum var. latifolium