Thelomma occidentale
Description 2
Thallus: verrucose-subareolate; surface: gray, without isidia; cortex: 11-24 µm thick, hyaline; without crystals in cortex nor medulla, uniform, without strands of hyphae penetrating into the medulla, borderline of medulla even, parallel with surface; fertile verrucae: 1.2-1.8 mm in diam., with uneven surface; Apothecia: single in the fertile verrucae or rarely 2-3; mazaedium: 0.7-1 mm in diam., sometimes with a greenish-yellow pruina; exciple: 0.23-0.33 mm high, blackish brown; hymenium: 55-80 µm tall; asci: cylindrical, 8-spored, with uniseriate spores; ascospores: 1-septate, constricted at septum, 22-28 x 12-13 µm; surface: smooth or minutely uneven in light microscope; Spot tests: thallus K-, C-, KC-, P-; medulla I-; Secondary metabolites: thallus having several chemotypes: epanorin and rhizocarpic acid, usnic acid alone, or none detected; yellowish pruina of mazaedium with tetronic acid derivatives.; Substrate and ecology: on wood, preferably fence posts, sea level to 600 m; World distribution: southern Alaska to California; Sonoran distribution: southern California and Baja California.; Notes: Contrary to Herre (1910), the thallus of Thelomma occidentale is best described as effuse, without marginal lobation. The exciple is reduced to a dark cushion. As the spore mass pushes against the confining thallus, the adjacent tissue becomes slightly upturned, often creating a distinct white rim. The mazaedium often has a slightly greenish cast.
Description 2
Thallus: verrucose-subareolate; surface: gray, without isidia; cortex: 11-24 µm thick, hyaline; without crystals in cortex nor medulla, uniform, without strands of hyphae penetrating into the medulla, borderline of medulla even, parallel with surface; fertile verrucae: 1.2-1.8 mm in diam., with uneven surface; Apothecia: single in the fertile verrucae or rarely 2-3; mazaedium: 0.7-1 mm in diam., sometimes with a greenish-yellow pruina; exciple: 0.23-0.33 mm high, blackish brown; hymenium: 55-80 µm tall; asci: cylindrical, 8-spored, with uniseriate spores; ascospores: 1-septate, constricted at septum, 22-28 x 12-13 µm; surface: smooth or minutely uneven in light microscope; Spot tests: thallus K-, C-, KC-, P-; medulla I-; Secondary metabolites: thallus having several chemotypes: epanorin and rhizocarpic acid, usnic acid alone, or none detected; yellowish pruina of mazaedium with tetronic acid derivatives.; Substrate and ecology: on wood, preferably fence posts, sea level to 600 m; World distribution: southern Alaska to California; Sonoran distribution: southern California and Baja California.; Notes: Contrary to Herre (1910), the thallus of Thelomma occidentale is best described as effuse, without marginal lobation. The exciple is reduced to a dark cushion. As the spore mass pushes against the confining thallus, the adjacent tissue becomes slightly upturned, often creating a distinct white rim. The mazaedium often has a slightly greenish cast.
Fuentes y créditos
- (c) Richard Droker, algunos derechos reservados (CC BY-NC-ND), http://www.flickr.com/photos/29750062@N06/9685979725/
- (c) Lichen Unlimited: Arizona State University, Tempe., algunos derechos reservados (CC BY-NC-SA), http://eol.org/data_objects/10548152
Más información
NaturaLista Mapa
| Color | gray |
|---|---|
| Form | crustose |
| Morphological feature | apothecia |
| Substrate | wood |
