Sedum albomarginatum Clausen (1975: 424)

Zika, Peter F., Wilson, Barbara L., Brainerd, Richard E., Otting, Nick, Darington, Steven, Knaus, Brian J. & Nelson, Julie Kierstead, 2018, A review of Sedum section Gormania (Crassulaceae) in western North America, Phytotaxa 368 (1), pp. 448-450 : 448-450

1. Sedum albomarginatum Clausen (1975: 424) . Figs. 8A , 15A , 21

Type: — UNITED STATES. California: Plumas Co., Serpentine Canyon, East Branch of North Fork of Feather River, 855 m, 6 June 1963, R. T . Clausen 63169 (holotype, BH; isotype, R. T. Clausen 63172 BH) .

Clausen, when preparing his type, provided different collection numbers for his replicates. Nonetheless, he indicated on his labels that he considered Clausen 63172 ( BH) to be an isotype collection of Sedum albomarginatum , and that Clausen 63169 ( BH) was the holotype. Both sheets were hand-labeled by Clausen, and collected at the same site on the same day, so we agree with Clausen that they represent one gathering of the type material, even with different collection numbers. Some additional live replicates were also gathered and used in his greenhouse studies, but these did not survive long in cultivation ( Clausen 1975).

Additional specimens examined: — UNITED STATES. CALIFORNIA. Butte County: Feather River Canyon, 9 June 1961, Hutchison 2101 ( JEPS); same site, 15 May 2012, Zika 25867 ( WTU) . Plumas County: Feather River Canyon, 19 June 1963, Clausen 63178 ( BH); same site, 9 June 1961, Hutchison 2126 ( JEPS, K internet image); E Branch of N Fork of Feather River , 6 June 1967, Hutchison 7333 ( JEPS); canyon of the N Fork of Feather River, 915 m, 8 June 1943, Youngs s.n. [= Clausen C43-55 ] ( BH, ex herb. Clausen ); same site, collected living 9 June 1961, pressed 14 June 1961, Hutchison 2122 ( F, JEPS, K internet image, NY, RSA) ; Feather River Canyon , N side of E Branch of N Fork, 26 June 1961, Uhl 965a & Hutchison ( JEPS); same site, 26 June 1961, Uhl 968 & Hutchison ( JEPS); N Fork Feather River, Serpentine Canyon , 853 m, 13 June 1976, Denton 3853 ( WTU); same site, 22 April 1977, Denton 4060 ( WTU); N Fork Feather River, 750 m, 13 June 1976, Denton 3861 ( WTU); same site, 15 May 2012, Zika 25865 ( JEPS, WTU); divide between Yellow Creek and Caribou Canyon, 1455 m, 6 August 2011, Wilson et al. CWG-16 ( OSC) .

Distribution and ecology: — Sedum albomarginatum was restricted to Butte and Plumas counties in California, along the drainage of the North Fork of the Feather River and its tributaries ( Fig. 22 ), where it grew on strongly serpentine bedrock, except for a northern population on a metasedimentary substrate. Recorded elevations ranged from 480–1740 m, in the northern High Sierra Nevada ecoregion (Jepson eFlora 2017). Sedum albomarginatum was rare, with a limited distribution and few populations, although some of the populations were large.

Notes:— Sedum albomarginatum ( Fig. 21 ) had oblanceolate rosette and stem leaves with a thick and granular waxy indument that rubbed off easily when the plant was handled. The leaves rarely had white margins. The inflorescence branches and sepals were also granular-waxy, and the outer surface of the petals could also bear a few granules of wax early in the season. The sepals were about half as long as the petals, and the petal tips were ascending. At the start of flowering the petals were a clear pale yellow ( Fig. 8A ), with a pale or slightly darkened midvein, fading to orangebrown ( Fig. 15A ). The fresh anthers were yellow, aging to white or brown.

Sedum oblanceolatum was a closely related species ( Table 5) from the Siskiyou Mountains in the Klamath Ranges ecoregion of California and adjacent Oregon ( Meyers et al. 2015, Jepson eFlora 2017). It was similar to S. albomarginatum in that both had thick granular waxy deposits early in the growing season, and that the oblanceolate rosette leaves gradually transitioned to the similarly-shaped stem leaves. The two species were disjunct by 250 km ( Fig. 22 ), and differed in flower color. Sedum oblanceolatum had consistently white corollas, proportionately narrower leaves, and often smaller plants. The leaves of both taxa quickly lost their wax to weathering unless sheltered by a rock overhang.

Sedum marmorense also had a thick waxy coating on leaves, inflorescence branches, sepals and sometimes on the pale yellow flowers, but its rosette and stem leaves were proportionally broader, and it grows in the Klamath Ranges ecoregion of Siskiyou County, California, 200 km northwest of S. albomarginatum ( Fig. 22 ).

Clausen (1975: 429–433) reported a pungent odor to the flowers, and nocturnal moth visitors, based on the observations of Paul Hutchison.

Figures

FIGURE 8. The central basal flower in a cyme was the largest and opened first.A. Sedum albomarginatum, Plumas Co., California (Zika 25865). B. Sedum citrinum, Del Norte Co., California (Zika 26201). C. Sedum laxum subsp. laxum, Del Norte Co. (Zika 25927). D. Sedum paradisum subsp. paradisum, Shasta Co., California (Lindstrand III & Van Susteren NSR-01). E. Sedum patens, Del Norte Co. (Zika 26609 & Brainerd).

FIGURE 15. The color of the petals, anthers, filaments, and carpels often changed after anthesis.A. Sedum albomarginatum, after anthesis petals turned orange-brown; Butte Co., California (Zika 25867). B. Sedum flavidum, buds deep pink especially along the keel, faded to white at anthesis, then aged to a uniform deep pink; Humboldt Co., California (Wilson, Otting, & Darington CWG-118). C. Sedum laxum subsp. laxum, after anthesis green carpels turned dark red, red anthers turned white; Del Norte Co., California (Zika 25936). D. Sedum paradisum subsp. subroseum, after anthesis green carpels turned dark red, yellow anthers turned white; Plumas Co., California (Wilson, Zika & Janeway CWG-15). E. Sedum rubiginosum, after anthesis red-based yellow petals turned pallid; Tehama Co., California (Zika 26234).

FIGURE 21. Sedum albomarginatum. A. Habit. B. Two flowering stems, the oblanceolate rosette leaves and stem leaves were similar in length and outline, the stem leaves were consistently elongated proximally and distally. C. Rosette leaves, fresh ones waxy, older weathered ones green. D. Stem leaves, showing truncated base. E–G. Dense white granular wax coating on fresh leaves, bracts and sepals, easily rubbed off on fingers. F. Flower and bud, showing erect pale yellow petals, white granular wax coating was dense on fresh sepals and bracts, sparse on corolla. G. Densely white granular waxy rosette leaves. A–D, G. Plumas Co., California (Zika 25865). E–F. Butte Co., California (Zika 25867).

FIGURE 22. Distribution of Sedum albomarginatum, S. citrinum, S. marmorense, S. moranii, S. oblanceolatum, and S. patens, based on verified herbarium specimens.