Bryological and Lichenological Section/ABLS
Stone, Daphne F. , Ruchty, Andrea .
Small Epiphytic Leptogium Species in the Pacific Northwest.
THE Pacific Northwest hosts a diverse group of small epiphytic Leptogium species. Despite a number of recent taxonomic revisions, clarifications and additions, this group remains difficult to identify with the descriptions available. The defining characters used, such as thallus color, structure of the medulla, extent of thallus wrinkling, and isidia type, are highly variable. The purpose of our study is to examine and compare a subset of these epiphytic Leptogium species and fully describe each one by defining a range of variation for characters that are directly comparable between species. Traditionally, the medulla has been divided into three types based on structure: loosely interwoven, cellular (paraplectenchymatous), and L. intermedium type (loosely interwoven hyphae of length to width ratio about 10:1). Our observations reveal more variation in medulla structure than previously reported; a thin thallus cross-section provides a reliable means for distinguishing some of the species. Medulla structure and external characters such as isidia shape, spore size and thallus thickness, clarify species definition. Of particular interest to Pacific Northwest federal land managers is our finding that Leptogium cyanescens, listed as a Forest Service Sensitive species in Region 6, a BLM Tracking species in Washington and Oregon, and a Survey and Manage category A species across the Northwest Forest Plan area, is less common than earlier reported. This species is clearly defined by a thin thallus with medulla of hyphae that are oriented perpendicular and parallel to the cortices, producing a basket-weave effect. A previously undescribed species has also been discovered, with adnate lobes, coralloid, primarily marginal isidia, and a paraplectenchymatous interior. This species has been found from northern California to southern Oregon.
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1 - 30567 Le Bleu Road, Eugene, Oregon, 97405-9216, USA
2 - Gifford Pinchot National Forest, Trout Lake, Washington, 98650-9724, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM