Allocetraria madreporiformis (Ach.) Kärnefelt & A. Thell
Nomenclatural data
Nova Hedwigia 62: 508, 1996. – Dufourea madreporiformis Ach., Lich. Univ.: 525, 1810. – Type: Helvetia [Switzerland], Acharius (H-ACH 1507! – lectotype, selected here). – Dactylina madreporiformis (Ach.) Tuck., Proc. Amer. Acad. Arts Sci. 5: 398, 1862. – Cetraria madreporiformis (Ach.) Müll. Arg., Flora 53: 325, 1870. – Dufourea madreporiformis var. irregularis Vain., Bot. Tidsskr. 26: 241, 1904. – Type: [Kirghisia] Western Tjanschan, Talas Alatau, Tjuss Aschu, alt. 13 500 feet, 1898–99, B. Fedtschenko, Herb. Vainio No. 01151 (TUR!). – Dactylina madreporiformis f. irregularis (Vain.) Lynge, Skr. Svalbard Ishavet (Oslo) 59: 39, 1933.
Morphology
Typical characters. Thallus yellow to brown, radially symmetric, slightly inflated, becoming arachnoid in the center. Medulla white. Pycnidia immersed or slightly emergent.
Chemistry
Contains usnic acid in the cortex and a lichesterinic-protolichesterinic type fatty acid in the medulla.
Remarks
In the typical form this taxon is easily recognized by the radially symmetric thallus and white medulla. The variety Dactylina madreporiformis var. irregularis (Vain.) Lynge has been referred to as having a distinctly dorsiventral thallus (Thomson & Bird 1978). However, the original description of this taxon (... vulgo leviter compressis aut plus minusve irregulariter subcylindricis ...) (Vainio 1904) as well as the type material demonstrate that this is not correct – the thallus of var. irregularis is inflated, obviously radially symmetric and occasionally slightly compressed. Therefore the collections with distinctly flat lobes from Colorado in North America reported by Weber & Shushan (1955) and Imshaug (1957) are, in our opinion, A. stracheyi rather than A. madreporiformis.
Ecology and distribution
This is the most widely distributed Allocetraria species which occurs in the arctic and alpine areas of North America and Asia, and in the mountains of central Europe. In Asia it is known from China (Qinghai, Xinjiang, Xizang and Yunnan provinces), Kirghizia, Mongolia, and Russia (Wei, 1991; Kärnefelt & Thell 1996). Grows on soil, preferably calcareous soils.
Literature:
Randlane, T. & Saag, A. 1993. | Randlane, T. & Saag, A. 2004. | Randlane, T., Saag, A. & Obermayer, W. 2001. | Randlane, T., Saag, A. & Thell, A. 1997. | Thell, A., Randlane, T., Kärnefelt, I., Gao, X. & Saag, A. 1995.
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