Slideshow image
Chaenotheca spp.
Family: Coniocybaceae
Chaenotheca image
Stephen Sharnoff  
Life habit: lichenized Thallus: crustose, superficial or immersed, farinose, granular, verrucose or squamulose surface: gray, greenish gray, golden yellow, brownish, or bright yellow-green photobiont: primary one a species Dictyochloropsis, Stichococcus, Trentepohlia or Trebouxia, secondary one absent Ascomata: apothecial, with short to long stalk stalk: consisting of periclinally arranged brown hyphae capitulum: globose to obconical; thalline exciple: absent proper exciple: +well developed, formed by periclinally arranged, +intertwined hyphae and continuous with stalk tissue; hypothecium: medium brown, with convex to flat upper surface mazaedium: well developed, pale brown to medium brown; paraphyses: sparingly branched, continuing to grow into the ascospore mass asci: cylindrical, ellipsoid or irregular, dissolving at an early stage, formed from ascogenous hyphae with or without croziers, either singly or in chains ascospores: simple or rarely 1-5-septate, brown to pale brown, forming a dry brown spore mass, globose or ellipsoid-cylindrical, 2.5-9 x 2.5-7.5 µm; wall: +thick, smooth or with an ornamentation of irregular cracks Conidiomata: forming several types: both coelomycetous (pycnidial), spherical with apical ostiole, or hyphomcetous, simple, Phialophora-like; pycnidium wall: thin and consisting of one or a few layers of radially arranged cells; wall-forming cells: with a thick pigmented layer at their distal surface; conidiogenous cells: simple, ellipsoid to cylindrical conidia: acrogenous, hyaline, one-celled, 2-3 x 1 µm Secondary metabolites: pulvinic acid derivatives occur as a pruina and more rarely within the thallus, ß-orcinol depsides and pseudoplacodiolic acid Substrate: mainly on bark and wood, rarely on soil and rocks, mostly in very sheltered situations with high humidity and low light levels Geography: cosmopolitan, mostly cool to temperate. Notes: See Tibell (1999) for fuller description of the genus.
Species within Rocky Mountain National Park