Details - A monograph of the lichen genus Relicina (Parmeliaceae)

A monograph of the lichen genus Relicina (Parmeliaceae)

Title

A monograph of the lichen genus Relicina (Parmeliaceae)

Related Titles

Series: Smithsonian contributions to botany, no. 26

By

Hale, Mason Ellsworth, Jr., 1928-1990

Type

Book

Material

Published material

Publication info

Washington, Smithsonian Institution Press, 1975

Notes

A revision is made for 77 species of Hypotrachyna occurring in tropical America. Fifty-eight of these are endemic to the New World. These species are classified loosely in chemical constellations based on the secondary depside-depsidone products. The possible role of hybridization of fertile species and the evolution of vegetative morphs are discussed. Five new species are described: H. andensis, H. lopezii, H. partita, H. producta, and H. protenta. The remaining 72 species are transferred from the genus Parmelia to Hypotrachyna.A revision on the world level is made for Relicina, a generic segregate of Parmelia characterized by having bulbate cilia on the lobe margins and by producing usnic acid in the cortex. Of the 24 species presently known, 19 occur in the Old World tropics, with the greatest concentration in the lowland dipterocarp forests, 3 are endemic to the New World tropics, and 2 occur in both the New and Old World outside of Africa. The most important taxonomic characters are type of rhizine (simple or branched), presence of coronate apothecia, isidia, and chemistry. The major chemical constituents are echinocarpic acid, fumarprotocetraric acid, and protocetraric acid. The genus is considered to be of fairly recent origin but rather conservative in terms of morphological and chemical evolution. Four new species, R. amphithrix, R. incongrua, R. precircumnodata, and R. subconnivens, are described and one new combination, R. relicinula (Müller Argau) Hale, is made.