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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Disease and Pest Management Research Unit » Research » Publications at this Location » Publication #348211

Research Project: Integrated Disease Management of Exotic and Emerging Plant Diseases of Horticultural Crops

Location: Horticultural Crops Disease and Pest Management Research Unit

Title: A review of Sedum section Gormania (Crassulaceae) in western North America

item ZIKA, PETER - University Of Washington
item WILSON, BARBARA - Carex Working Group
item BRAINERD, RICHARD - Carex Working Group
item OTTING, NICK - Carex Working Group
item DARINGTON, STEVEN - Consultant
item Knaus, Brian
item NELSON, JULIE - Us Forest Service (FS)

Submitted to: Phytotaxa
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2018
Publication Date: 9/10/2018
Citation: Zika, P.F., Wilson, B.L., Brainerd, R.E., Otting, N., Darington, S., Knaus, B.J., Nelson, J.K. 2018. A review of Sedum section Gormania (Crassulaceae) in western North America. Phytotaxa. 368(1):1-61.

Interpretive Summary: The plant genus Sedum includes plants that are native to Oregon, Nevada, and California. We examined vegetative and floral characters in order to address questions of taxonomy within the group. Results from these analyses contributed to the reclassification of 17 members of the group and acceptance of four new members. This work is intended to aid land managers and enthusiasts in the identification of these plants.

Technical Abstract: Sedum section Gormania was restricted to Oregon, Nevada and California in the western United States. After extensive field work from 2011 to 2014, we reclassified 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, 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. Apparent cleistogamy was observed in the late season flowers of four taxa.