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Thalloconidia in the genus Umbilicaria
Author(s) -
Hestmark Geir
Publication year - 1990
Publication title -
nordic journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.333
H-Index - 33
eISSN - 1756-1051
pISSN - 0107-055X
DOI - 10.1111/j.1756-1051.1990.tb00546.x
Subject(s) - thallus , biology , botany , lichen , conidium , genus , propagule , taxon
Hypothalline, hyphomycetous anamorphs ‐ thalloconidia ‐ from 18 taxa in the lichen genus Umbilicaria have been studied in detail with the aid of scanning and transmission electron microscopy. These asexual propagules are brown to dark brown, single‐to multi‐cellular (up to 2500 cells), spherical to irregular, smooth to rugged; their walls two‐ or three‐layered. The thalloconidia are produced and seceded directly from the cortex and/or the rhizinomorphs on the lower side of the thallus. Conidiomata and conidiophores are absent. The characteristics of the thalloconidia prove to be of substantial value for taxonomical work at the specific level. The anamorphs of U. antarctica and U. esculenta are described for the first time. Thirty‐five taxa from the genus Umbilicaria and 10 from the genus Lasallia were screened for the occurrence of thalloconidia with negative result.