Sedum laxum

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

6b. Sedum laxum (Britton in Britton & Rose 1903: 29) Berger (1930: 451) subsp. laxum . Figs. 1B , 5B , 7 , 8C , 10A–D , 14C–D , 15C , 16A–B , 31 .

Sedum laxum (Britton) A.Berger subsp. latifolium Clausen (1942: 38) . Sedum laxum (Britton) A.Berger var. latifolium (R.T.Clausen) Ohba

(2007: 890). Type: — UNITED STATES. California: Del Norte County, rocky slope along Smith River, 24 miles NE of Crescent City , 457 m, 24 July

1940, R. T. Clausen 4941 & H. Trapido (holotype, BH; isotypes, BH, NY). Sedum laxum (Britton) A.Berger subsp. perplexum Clausen (1942: 36) . Type: — UNITED STATES. Oregon: [Curry County], cliff near [2 miles above] mouth of Rogue River , 8 July 1919 , M. E. Peck 8703

( holotype, BH; isotype, WILLU) .

Additional specimens examined:— UNITED STATES. CALIFORNIA. Del Norte County: Gasquet to Patricks, 27 June - 1 July 1922, Abrams 8515 ( POM), Abrams 8516 ( DS, WTU); Patrick Creek, 2 July 1936, Eastwood & Howell 3646 ( CAS); 10 miles NE of Crescent City, 12 July 1923, Peirson 3958 ( RSA); cultivated in greenhouse, source: Smith River 24 miles NE of Crescent City, 24 June 1944, Clausen C 4941 ( WTU); 18 Mile Creek, 152 m, 5 July 1963, Howe s.n. ( SD); Smith River at Stoney Creek, 107 m, 23 May 1972, Wallace 1081 & DeBuhr ( RSA); Hiouchi Flat, 15 June 1951, Moran 3486 ( BH); E of Hiouchi, 80 m, 10 June 2012, Brainerd & Otting CWG-104 ( OSC, UCR); same site, 23 June 2012, Zika 25927 ( OSC, UCR, WTU); above Gasquet, 15 June 1951, Moran 3487 ( BH, CAS, UC); SW of Gasquet, Denton 4002 ( OSC, WTU); between Patricks Creek and Gasquet, 180 m, 22 June 2014, Wilson 18122 & Otting ( OSC); Gasquet, 100 m, 24 June 2012, Zika 25936 ( NY, US); S of Idlewild, 17 June 1951, Dress 3394 ( BH); same site, 24 May 1961, Hutchison 2081 ( BH); Idlewild, 375 m, 10 June 2012, Brainerd & Otting CWG-107 ( DAV, HSC, KANU, RSA, STNF); between Crescent City and Oregon line, 29 June 1941, Winblad s.n. ( CAS); Sanger Peak Road, 1615 m, 27 July 1949, Whittaker SS 264- S ( WS); Middle Fork Smith River, 365 m, 29 June 1976, Denton 4001 ( NY, OSC, WTU); ENE of Crescent City, 76 m, 24 April 1977, Denton 4074 ( WTU); SE of Cave Junction, 1135 m, 28 June 1976, Denton 3991 ( WTU); below Myrtle Creek, 60 m, 16 June 1937, Wolf 8856 ( RSA); same site, 10 July 1961, Uhl 956 [= Hutchison 2082] ( BH, JEPS); Oregon Mountain, 960 m, 15 June 1951, Moran 3488 ( UC); Gordon Mountain, 1250 m, 22 June 2014, Wilson 18124 & Otting ( OSC). Siskiyou County: Siskiyou Mountains, WSW of Cyclone Gap, larvae of Callophrys mossii , Moss’ elfin, Lepidoptera : Lycaenidae , feeding on flowers, 1615 m, 16 July 1974, Emmel 512 ( RSA). OREGON. Curry County: Snow Camp Forest Lookout, July 1951, Vollmer & Beane 174 ( DS); same site, 1 July 1976, Denton 4006 ( WTU); Vulcan Peak, 1106 m, 3 July 1973, Denton 3021 ( WTU); same site, 30 June 1976, Denton 4003 ( WTU); W of Vulcan Peak, 1160 m, 15 June 1975, Denton 3691 ( WTU); Pyramid Rock, 1220 m, 22 June 1936, Thompson 12855 ( BH, CAS, RSA, WILLU, WS, WTU); same site, 1 July 1976; Denton 4005 ( OSC, WTU); Hunter Creek Road, 565 m, 1 July 1976, Denton 4004 ( WTU); Gold Beach, 25 m, 1 July 2013, Wilson & Otting CWG-240 ( OSC, WTU). Douglas County: Beatty Creek Research Natural Area, 625 m, 28 May 1987, Zika 10382 ( OSC). Josephine County: Waldo, 7 July 1887, T. Howell s.n. ( PH internet image); same site, 19 June 1932, Applegate 7290 ( DS); S of Waldo, 610 m, 1 August 1940, Clausen 5018 & Trapido ( BH [3 sheets], DS); cultivated from same site, 25 July 1942, Clausen C 5018 ( BH); near Waldo, 10 July 1961, Hutchison 2074 [= Uhl 952] ( BH); Waldo Road, 590 m, 27 June 1976, Denton 3982 ( OSC, WTU); same site, 24 April 1977, Denton 4076 ( WTU); S of O’Brien, toll road to Gasquet, California, 10 July 1961, Hutchison 2076 [= Uhl 953] ( BH, DS); W of Selma, 505 m, 2 July 1976, Denton 4010 ( WTU); same site, 25 April 1977, Denton 4081 ( WTU); Rogue River above Galice, 230 m, 31 July 1940, Clausen 5015 & Trapido ( BH [3 sheets]); same site, 23 May 1961, Hutchison 2063 [= Uhl 946] ( BH, SD); same site, 28 May 1963, Clausen 63148 ( BH); same site, 8 June 1963, Clausen 63149 ( BH); S of Galice, 325 m, 2 July 1976, Denton 4008 ( OSC, WTU); same site, 21 April 1977, Denton 4057 ( WTU); Wimer Road, 455 m, 5 July 1949, Whittaker SS 105- S ( WS); Eight Dollar Mountain, 17 June 1932, Applegate s.n. ( DS); SW of Eight Dollar Mountain, 515 m, 9 June 2013, Zika 26209 ( GH, NY, OSC, WTU); ENE of Fiddler Mountain, 800 m, 20 July 2011, Zika 25655 ( CAS, F, GH, KANU, UCR, US, WTU); SSE of Cave Junction, 615 m, 27 June 1976, Denton 3986 ( WTU); en route to Babyfoot Lake, 600 m, 28 June 1976, Denton 3993 ( WTU); E edge of Kalmiopsis Wilderness, 1340 m, 30 July 1977, Denton 4125 ( WTU); SE of Serpentine Mountain Lookout, 1050 m, 2 July 1976, Denton 4009 ( WTU); N of Tennessee Mountain, 460 m, 2 July 2011, Zika 25487 ( CAS, WTU); same site, 20 July 2011, Zika 25654 ( HSC, KNFY, MO, OSC, UC); NNE of Buckhorn Mountain, 255 m, 3 June 2017, Zika 28801 ( WTU).

Distribution and ecology: —Inland mountains, river canyons, and coastal bluffs in Josephine and Curry counties, south to Del Norte and Siskiyou counties, California, usually on serpentine substrates in the Klamath Ranges (Jepson eFlora 2017). Habitats included rocky slopes, ridges, knolls, talus, and ledges, usually in full sun and on dry thin soils, at elevations of 45–1646 m. Populations of Sedum laxum subsp. laxum were found north and west of subsp. heckneri ( Fig. 27 ).

Notes: — Sedum laxum subsp. laxum ( Fig. 31 ) had stem leaves longer than wide, ascending, not clasping, thick or thin, decurrent or not, crowded or not. Rosette and stem leaves were flat or distinctly thickened, and varied in color from green and waxless to blue-green and thinly glaucous, or pink. The sepals were relatively short and often acuminate, but varied to acute. The petal tips were narrow, acuminate, erect or nearly so, and pink with white margins, rarely entirely white. The fresh anthers were dark red, rarely red orange, senescing black or white.

Plants treated here as Sedum laxum subsp. laxum were further subdivided into thick-leaved S. laxum subsp. latifolium of the Smith River drainage in northwest California, thin-leaved S. laxum subsp. laxum of inland mountains, and small S. laxum subsp. perplexum with crowded, slightly thickened stem leaves, at the coast ( Fig. 27 ). These minor expressions were not worth separating, with many intermediate plants not easily placed.

Sedum laxum subsp. latifolium was submerged into S. laxum subsp. laxum by Denton (1979a, 1979b, 1982, 1993; Boyd & Denton 2012). Ohba (2007) resurrected the concept of subsp. latifolium (as var. latifolium ). Following Clausen (1975: 394), Ohba (2009), commented that subsp. latifolium (as var. latifolium ) was the “most robust” infraspecific taxon within S. laxum . Well-developed plants of S. laxum subsp. latifolium were robust compared to most members of Sedum section Gormania , but were not unusually large compared to S. laxum subsp. laxum and subsp. heckneri . We measured stem heights up to 48 cm for subsp. laxum from Josephine County, Oregon (Zika 28801), more robust than the maximum reported height of 40 cm for subsp. latifolium (as var. latifolium ) provided by Ohba (2009). At their extremes, the strongly glaucous and somewhat flattened rosette leaves of S. laxum subsp. laxum , when fresh ( Fig. 31B ), were different from the green, nearly waxless, and plump fresh rosette leaves of subsp. latifolium ( Figs. 1B , 31A ), in the Smith River basin. However, we found both flat and plump rosette leaves on plants at the subsp. latifolium type locality in 2013. Similarly, plants of subsp. laxum from low elevation (255 m) along the Rogue River showed some green rosette leaves that were plump and as much as 5.5 mm thick, while other rosette leaves were relatively thin and more glaucous (Zika 28801). In the Smith River basin, subsp. latifolium stem leaf bases were usually truncate. However, a few were decurrent, such as Wallace 1081 & DeBuhr ( RSA), and thus transitional to the concept of subsp. laxum . As we defined it, subsp. laxum populations most commonly had decurrent leaf bases outside the Smith River basin. But there were exceptions, and some plants or populations had stem leaf bases that were not decurrent, though usually decurrent leaves could be observed on other leaves or stems of the same plant, or on nearby plants. Again, the low elevation plants on the Rogue River (Zika 28801) were instructive, showing a mix. Decurrent or truncate stem leaf bases were present on different plants, as well as a number of intermediate forms.

Sedum laxum subsp. perplexum lived near the mouth of the Rogue River and south, close to the Oregon coast. The plants were small and erect, unlike typical plants of either S. laxum subsp. latifolium or S. laxum subsp. laxum . Their stem leaves were overlapping and usually not decurrent. The rosette and stem leaves were green and somewhat thickened, though not quite so plump as was typical of S. laxum subsp. latifolium . Short coastal plants were a morphological extreme, easily distinguished from robust inland S. laxum subsp. laxum , but size appeared to vary continually over the Siskiyou Mountains.

Although some populations within the Sedum laxum subsp. laxum complex were easily distinguished, many were intermediate between the named forms. Treating them all as a single taxon was appropriate.

Figures

FIGURE 1. Dense rosettes on vegetative shoots, without visible internodes between the leaves, were found in most species. A. Sedum flavidum, Trinity Co., California (Zika 26646 & Brainerd). B. Sedum laxum subsp. laxum, Del Norte Co., California (Zika 25927). C. Sedum oblanceolatum, Jackson Co., Oregon (Zika 25636 & Lang). D–E. Sedum rubiginosum, Tehama Co., California. D. Wild plant (Zika 26238). E. Cultivated plant (Wilson & Coberly CWG-10). F. Sedum sanhedrinum, Mendocino Co., California (Zika 26629 & Brainerd).

FIGURE 5. Stem leaves longer than wide, with a truncated base, were typical of most species of Sedum section Gormania. The stem leaves were commonly broadly obovate to elliptic or oblong, and were flattened or nearly cylindrical.A. Sedum citrinum, Del Norte Co., California (Zika 26185). B. Sedum laxum subsp. laxum, Del Norte Co. (Zika 25927). C. Sedum oblanceolatum × oregonense, Siskiyou Co., California (Zika 25647B). D. Sedum obtusatum, Nevada Co., California (Zika 26271). E–F. Sedum oregonense, Josephine Co., Oregon (Zika 25657). G. Sedum sanhedrinum, Lake Co., California (Zika 26639 & Brainerd).

FIGURE 7. Stem leaf bases were decurrent in some individuals of Sedum laxum subsp. laxum. A–D. Josephine Co., Oregon. A–C. Zika 25655. D. Zika 26209.

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 10. The petal tips erect and acuminate, essentially parallel to the floral axis.A–D. Sedum laxum subsp. laxum. A–B. Curry Co., Oregon (Wilson & Otting CWG-240). C–D. Josephine Co., Oregon (Zika 25655). E. Sedum moranii, Josephine Co. (Zika 25631).

FIGURE 14. Cultivated individuals often had petals more widely spreading than in the wild. A–B. Sedum flavidum corollas, Humboldt Co., California (Brainerd & Otting CWG-103). A. Ascending petals, wild plants. B. Spreading petals, cultivated plants. C–D. Sedum laxum subsp. laxum corollas, Del Norte Co., California. C. Erect petals, wild plants (Brainerd & Otting CWG-107). D. Ascending petals, cultivated plants (Brainerd & Otting CWG-104). E–F. Sedum sanhedrinum corollas, Tehama Co., California. E. Erect petals, wild plants (Zika 26244). F. Ascending petals, cultivated plants, Tehama Co. (J.K. Nelson JKN-2).

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 16. Some taxa occasionally produced paler flowers in cultivation.A–B. Sedum laxum subsp. laxum. A. Pink petals, wild plants, Del Norte Co., California (Zika 25927). B. Fresh white petals with faint pink background, turning darker pink with age, cultivated, from Josephine Co., Oregon (Zika 25487). C–D. Sedum paradisum subsp. paradisum, Shasta Co., California. C. Yellowish petals, fading pinkish-orange, wild plants (Zika 25924). D. White petals, cultivated (Lindstrand III & Van Susteren NSR-07).

FIGURE 27. Distribution of the pink-flowered taxa Sedum eastwoodiae, S. laxum subsp. heckneri, and S. laxum subsp. laxum, based on verified herbarium specimens.

FIGURE 31. Sedum laxum subsp. laxum. A–C. Dense rosettes on sterile shoots. A. Relatively plump rosette leaves, green to faintly glaucous, corresponding to the type of S. laxum subsp. latifolium, Del Norte Co., California (Zika 25927). B–C. Relatively thin rosette leaves, moderately glaucous and blue-green, Josephine Co., Oregon (Zika 25655). C. Rhizomes and stolons to 40 cm, bearing rosettes. Scale 15 cm. D–G. Stem leaf variation. D–E. Typical stem leaves, longer than wide, thin, base decurrent. D. Gray stem leaves, Josephine Co. (Zika 26209). E. Red stem leaves, Josephine Co. (Zika 25655). F. Transitional stem leaves, thin, slightly decurrent at base, Del Norte Co. (Brainerd & Otting CWG-107). G. Plump stem leaves, truncated at base, corresponding to the type of S. laxum subsp. latifolium, Del Norte Co. (Zika 25927). H–K.Inflorescence variation. H–I. Flat-topped inflorescences. H. Low coastal plants, corresponding to the type of S. laxum subsp. perplexum; Curry Co., Oregon (Wilson & Otting CWG-240). I. Tall inland plants; Del Norte Co. (Zika 25927). J. Capitate inflorescence (Brainerd & Otting CWG-107). K. Cylindrical inflorescence, Josephine Co. (Zika 26209). L–O. Pink flowers, darkened with age, red anthers, erect petals with acuminate tips, elongate acuminate sepals; Del Norte Co. L. Dark pink flowers (Zika 25927). M–O. Pale pink flowers. M, O. Subapical mucro prominent and extended past the petal apex (Zika 25936). N. Narrow sepals (Brainerd & Otting CWG-107).