Sedum laxum

(Britton) A. Berger in H. G. A. Engler et al.

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

Endemic
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 rootstocks, 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, redbrown, or yellow; nectar scales white, yellow, or pink, reniform or transversely oblong. Carpels erect in fruit, distinct, brown.

Discussion

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

None.

Key

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
... more about "Sedum laxum"
perigynous +  and hypogynous +
yellow +, redbrown +, reddish purple +  and red +
aristate +, mucronate +, obtuse +, subacute +, acute +, truncate +  and rounded or obtuse emarginate or barely notched +
Hideaki Ohba +
(Britton) A. Berger in H. G. A. Engler et al. +
not scarious +
Gormania laxa +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
not pruinose +
1 cm10 mm <br />0.01 m <br /> (5 cm50 mm <br />0.05 m <br />) +
lobed +  and toothed +
not +  and glaucous +
flattened +, subterete +, obovate +, spatulate +  and oblanceolate +
0.1 cm1 mm <br />0.001 m <br /> (8 cm80 mm <br />0.08 m <br />) +
succulent +
0.6 cm6 mm <br />0.006 m <br /> (3.3 cm33 mm <br />0.033 m <br />) +
smaller +
not recurved +
2-forked +
not circumscissile +
whorled +, opposite +  and alternate +
not circumscissile +
3+-branched +  and 12-80-flowered +
Calif. +  and Oreg. +
pink +, greenish white +  and white +
connate +  and distinct +
spreading;erect +
axillary +  and terminal +
suborbiculate;obovate;suborbiculate;obovate;spatulate;oblanceolate +
persistent +  and deciduous +
connate +
erect +  and spreading +
pink +, yellow +  and white +
oblong +  and reniform +
spatulate;reniform;spatulate;reniform;oblong;square;oblong +
semi-inferior +  and superior +
tenuinucellate +, crassinucellate +  and bitegmic +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.63 cm6.3 mm <br />0.0063 m <br />) +
perigynous +  and hypogynous +
white +  and yellowish white +
not carinate +, elliptic-oblong +, oblanceolate-oblong +  and lanceolate-oblong +
0.4 cm4 mm <br />0.004 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
(3-)4-5(-12)[-30+]-carpellate +
distinct +  and connate +
in H. G. A. Engler et al., Nat. Pflanzenfam. ed. +
reticulate-papillose +  and reticulate +
ovoid;ellipsoid +
0.2 cm2 mm <br />0.002 m <br /> (0.26 cm2.6 mm <br />0.0026 m <br />) +
lanceolate +  and ovate +
unequal +
2 cm20 mm <br />0.02 m <br /> (?) +
1 +  and many +
branched +  and simple +
30 cm300 mm <br />0.3 m <br /> (40 cm400 mm <br />0.4 m <br />) +
decumbent +  and erect +
adnate +  and free +
antipetalous +
2 times as many as sepals +
much-branched +
creeping +  and procumbent +
ascending +  and erect +
succulent +
distinct +
Sedum laxum +
species +
not conspicuous +
perennial +, biennial +  and annual +
herb +, not +  and cespitose +
3 +  and 5 +