Tuesday, September 11, 2018

[Botany • 2018] A Review of Sedum section Gormania (Crassulaceae) in western North America

 Sedum laxum subsp. laxumSedum moranii,  
 Sedum citrinum, Sedum kiersteadiae, Sedum patens, Sedum rubiginosum, et al. ...

in Zika, Wilson, Brainerd, et al., 2018. 

Sedum section Gormania was restricted to Oregon, Nevada and California in the western United States. After extensive field work from 2011 to 2016, we revised 17 members of the group using floral and vegetative characters, resulting in the acceptance of four new taxa in California. A serpentine endemic from the mountains of western Tehama County was recognized as S. rubiginosum. It was separated from S. kiersteadiae by its dense rosettes, overlapping stem leaves and non-apiculate corolla. A serpentine endemic from low elevation canyons in Del Norte County was described as S. patens. It was distinguished from S. laxum by its white spreading petals and yellow anthers. A plant of high elevation, serpentine and non-serpentine sites in Siskiyou County was circumscribed as S. marmorense; it differed from S. oregonense in its sepals and inflorescence with a thick granular waxy deposit, and leaves in dense rosettes. Sedum paradisum was segregated from S. obtusatum, raised to species level, and divided into two subspecies. Plants of the northern Sierra Nevada were newly defined as S. paradisum subsp. subroseum, separable with nodding young flowering shoots and a disjunct range in Butte, Plumas and Sierra counties. Sedum flavidum and Sedum eastwoodiae were removed from S. laxum sensu stricto, and raised to species rank, based on floral characters. We clarified the concept of S. obtusatum subsp. retusum, and restored it to the rank of species as S. sanhedrinum; it was restricted to Glenn, Lake, Mendocino, and Tehama counties, California. Sedum flavidum and S. oregonense as defined here showed more morphological variation than previously understood. Finally, we remarked on hybridization and cleistogamy observed in the field.

Keywords: Sedum, new species, California, Eudicots

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 11. Petal tips narrow in the distal half; the petals strongly spreading to slightly reflexed.
A. Sedum citrinum, Del Norte Co., California (Zika 26620 & Brainerd). B. Sedum kiersteadiae, Trinity Co., California (Zika 26294). C. Sedum patens, Del Norte Co. (Zika 26609 & Brainerd). D. Sedum rubiginosum, Tehama Co., California (Zika 25522 & J.K. Nelson).
Figure 12. Variation in the width of the distal half of the petal in Sedum flavidum.
 A. Narrow-petaled extreme, Humboldt Co., California (Wilson 18112). B–D. Variation within a population, Trinity Co. (Zika 25922 & J.K. Nelson). B. Narrow-petaled extreme. C. Slightly narrowed petals. D. Typical broad petals. E. Slightly narrowed petals, Trinity Co., California (CWG-102a).
 Figure 13. Distal half of the petals broad and ascending.
A. Sedum flavidum, Trinity Co., California (J.K. Nelson JKN-12-2). B. Sedum i, Nevada Co., California (Zika 26271). C. Sedum oregonense, Del Norte Co., California (Otting CWG-122). D. Sedum paradisum subsp. i, Plumas Co., California (Wilson, Janeway & Zika CWG-14). 

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).

Taxonomic Treatment

1. Sedum albomarginatum Clausen (1975: 424). 

2. Sedum citrinum Zika (2014: 112). 

3. Sedum eastwoodiae (Britton in Britton & Rose 1903: 31) Berger (1930: 451).

4. Sedum flavidum (Denton 1978: 233) B.L. Wilson & Zika, comb. nov., stat. nov.
Sedum laxum (Britton in Britton & Rose 1903: 29) Berger (1930: 451) subsp. flavidum Denton (1978: 233) (basionym). Sedum laxum (Britton) A.Berger var. flavidum (Denton) Ohba (2007: 889).

5. Sedum kiersteadiae B.L.Wilson & R.E.Brainerd in Wilson et al. (2014: 9).

6. Sedum laxum (Britton in Britton & Rose 1903: 29) Berger (1930: 451)

6a. Sedum laxum (Britton in Britton & Rose 1903: 29) Berger (1930: 451) subsp. heckneri (Peck 1937: 121) Clausen (1942: 39). 
Sedum heckneri Peck (1937: 121). Sedum laxum (Britton) A.Berger var. heckneri (M.Peck) Ohba (2007: 889). 

6b. Sedum laxum (Britton in Britton & Rose 1903: 29) Berger (1930: 451) subsp. laxum
 Sedum laxum (Britton) A.Berger subsp. latifolium Clausen (1942: 38). Sedum laxum (Britton) A.Berger var. latifolium (R.T.Clausen) Ohba (2007: 890). 

7. Sedum marmorense Otting & R. E. Brainerd, sp. nov.  

 Species Sedum oblanceolatum proxima sed differt foliis basalibus rosulatis obovatis, a Sedum oregonensis rosulis densissimis et inflorescentiis granularibus ceraceisque.

Etymology:— Sedum marmorense, or Marble Mountains stonecrop, was named for the Marble Mountains and for the marble substrate on which it sometimes grows.

8. Sedum moranii Clausen (1942: 40).
 Cotyledon glandulifera Henderson (1930: 26). 
Sedum glanduliferum (L.F.Hend.) Peck (1941: 134). 
Gormania glandulifera (L.F.Hend.) Abrams (1944: 343).

9. Sedum oblanceolatum Clausen (1975: 404). 

10. Sedum obtusatum Gray (1868: 342). 
 Gormania obtusata (A.Gray) Britton in Britton & Rose (1903: 29). 
Cotyledon obtusata (A.Gray) Fedde in Schumann & Fedde (1904: 827). 
Echeveria obtusata (A.Gray) Nelson & Macbride (1913: 476). 

Figure 38. Sedum oregonense.
A. Habit, with numerous branched sterile shoots, Josephine Co., Oregon (Zika 25657). B–D. Stem leaves, varied from much longer than wide to ± as long as wide, truncated or slightly clasping at base. Colors varied from red to pink, orange, purplish, green or gray. B. Zika 25657. C. Linn Co., Oregon (Zika 25962). D. Clackamas Co., Oregon (Zika 25964). E. Loose rosettes, with easily visible internodes between leaves of the sterile shoots, slightly glaucous, Del Norte Co., California (Otting CWG-122). F. Nodding or arching young inflorescences, pre-anthesis, Lane Co., Oregon (Zika 27948). G–I, K. Inflorescences, varied from flat-topped to capitate or cylindrical. J–K. Flowers, petals typically white, rarely pale yellow, petals ascending, anthers yellow, Josephine Co. G. Del Norte Co. (Zika 25928). H–I, K. Josephine Co. H, K. Zika 25657. I–J. Brainerd & Otting CWG-243.

11. Sedum oregonense (Watson 1882: 373) Peck (1941: 361). 
Cotyledon oregonensis Watson (1882: 373). 
Gormania watsonii Britton in Britton & Rose (1903: 29). 
Echeveria watsonii (Britton) Nelson & Macbride (1913: 476). 
Sedum watsonii (Britton) Tidestrom in Dayton (1927: 119, as “watsoni”).

12. Sedum paradisum (Denton 1978: 236) Denton ex B. L. Wilson, stat. nov. 

Sedum obtusatum Gray (1868: 342) subsp. paradisum Denton (1978: 236) (basionym). Sedum obtusatum A.Gray var. paradisum (Denton) Ohba (2007: 889).

12a. Sedum paradisum (Denton 1978: 236) Denton ex B. L. Wilson subsp. paradisum.  

12b. Sedum paradisum (Denton 1978: 236) Denton ex B. L. Wilson subsp. subroseum B. L. Wilson & Zika, subsp. nov.
 Species nostra Sedum paradisum subsp. paradisum aemulans, differt axe inflorescentiae juvenili nutante, a Sedum obtusatum subsp. obtusatum floribus albis postea saepe pallide erubescentibus recedens.

Etymology:— Sedum paradisum subsp. subroseum, or Plumas stonecrop, was named for its flowers, which usually turned pinkish and with age gave the entire inflorescence a rosy appearance.

13. Sedum patens Zika, sp. nov.

Species insignis Sedum laxum eximie affinis sed petalis niveis apicibus patentibus necnon antheris luteis notabilis.

Etymology:— Sedum patens, or Smith River stonecrop, was named for the widely spreading petals.

Figure 43. Sedum rubiginosum, Tehama Co., California.
 A–C. Habitat, rocky serpentine slopes. A. Photo: J.K. Nelson (Zika 25522 & J.K. Nelson). B. Wilson & Coberly CWG-10. C. Zika 26238. D–E. Flowering shoots (Zika 25522 & J.K. Nelson). F. Dense rosettes (Zika 26234). G. Oblong overlapping ascending stem leaves, faintly glaucous, with truncated bases (Zika 26238). H. Cylindrical inflorescence in early anthesis, flowers dense (Zika 25522 & J.K. Nelson). I–K. Flowers, petals narrow, acute, spreading, reddish towards base, anthers dark red. I. Typical narrow petals (Zika 25522 & J.K. Nelson). J. Unusually broad petals (Zika 26238). K. Relatively short sepals (Zika 26234).

14. Sedum rubiginosum Zika & B. L. Wilson, sp. nov. 

 Differt haec species a Sedum kiersteadiae rosulis foliorum densis, floribus numerosioribus, sine vel reduci mucrone abaxiali subterminali, necnon foliis caulinis numerosis imbricatisque. 

Etymology:— Sedum rubiginosum, or Tedoc stonecrop, was named for the reddish colors found in the fresh and aged petals, as well as the rusty red anthers.

Figure 45. Sedum sanhedrinum
A. Habit, showing large rosette leaves and ascending stem leaves, Mendocino Co., California (Zika 26629 & Brainerd). B–D. Variation in stem leaves, spreading to ascending, broadly to narrowly obovate, bases truncated, slightly glaucous, green to purple or pink. B. Zika 26629 & Brainerd. C–D. Mendocino Co. (Zika 26633 & Brainerd). E. Dense and small rosette leaves, Tehama Co., California (Zika 26244). F. Capitate inflorescence, with dense flowers, Lake Co., California (Wilson & Otting CWG-231); inflorescences were also cylindrical (e.g., Fig. 45D, type) or flat-topped. G–K. Variation in flowers, corolla color pale yellow, orangeyellow, or bright yellow, faded to pink, orange-brown, pale brown, or yellow-brown, white or dull red; anthers yellow or, rarely, dull orange-red, faded to pink, reddish, white, or dull yellow; sepals elongated after anthesis. G. Tehama Co. (Wilson & Otting CWG-234). H. Zika 26629 & Brainerd. I. Zika 26633 & Brainerd. J–K. Petals erect, tips acute to blunt, Tehama Co. (Zika 25970).

15. Sedum sanhedrinum Berger (1930: 451). 
Gormania retusa Rose in Britton & Rose (1903: 31). 
Cotyledon retusa (Rose) Fedde in Schumann & Fedde (1904: 828). 
Sedum laxum (Britton in Britton & Rose 1903: 29) Berger (1930: 451) subsp. retusum (Rose) Clausen (1942: 39). 
Sedum obtusatum Gray (1868: 342) subsp. retusum (Rose) Clausen (1975: 375). 

Peter F. Zika, Barbara L. Wilson, Richard E. Brainerd, Nick Otting, Steve Darington, Brian J. Knaus and Julie Kierstead Nelson. 2018.  A Review of Sedum section Gormania (Crassulaceae) in western North America. Phytotaxa. 368(1); 1–61. DOI: 10.11646/phytotaxa.368.1.1