Allocetraria globulans (Nyl.) Thell & Randl.

Nomenclatural data
Basionym: Platysma globulans Nyl., Flora (Regensburg) 70: 134. 1887. - Cetraria globulans (Nyl.) Zahlbr., Trav. de Sous.-Sect. de Troitzkossawsk-Khiakta, Sect. du pays d’Amour de Soc. Imp. Russe de Geogr., 89, 1911 (1909). - Nephromopsis globulans (Nyl.) Lai, Quart. Journ. Taiwan Mus. 33: 222, 1980. - Type: China, Yunnan, Delavay, 1885, no. 1570 (H-NYL - 36 135, holotype; seen).
Morphology
Thallus foliose; upper surface yellowish (from light yellow to almost brown), lower surface brown, with sparse concolorous rhizines; lobes plane to concave, prolonged, up to 8 mm wide, dichtomously branched, secondary lobes usually quite narrow, about 1-1.5 mm wide. Pycnidia numerous marginally and a few laminally, located on black and somewhat emergent projections which often grow out from special warts of the thallus. Some pseudocyphellae-like structures may also be present on marginal warts. Upper cortex undistinctly palisade plectenchymatic, strongly crystallized, 15-30 µm, composed of 3-4 layers of equal-sized cells. Lower cortex similar to the upper but somewhat thinner and less crystallized, the lower cells brown-pigmented. Medulla is light yellow but specimens with white medulla also occur and sometimes the yellowish layer is seen on the lower parts of the thallus only.
Apothecia marginal and submarginal, up to 8 mm in diameter, disc brown, surrounded by yellowish thalline margin. Exciple 40-120 µm thick, asci narrowly to rather broadly clavate, 45–70 x 15–20 µm, tholus small, axial body very broad, 5–9 µm, ascospores globose, 7–10 µm in diameter or subglobose, 6.5-9 x 5-6.5 µm, more or less uniseriately arranged; pycnoconidia filiform and slightly sublageniform, 10-19 x 0.6-1 µm.
Chemistry
Usnic acid in the cortex; lichesterinic, protolichesterinic and secalonic acids A and C (+/-) in the medulla.
Remarks
Occasionally A. globulans is difficult to separate from A. stracheyi but the latter is always pale yellow and the lobes more prolonged and distinctly convex. The appearance of the ascus top and the pycnoconidial shape remove all doubts about the systematic position of the species.
Ecology and distribution
This epiphytic species is distributed in China (Yunnan county), Nepal (Langtang area and Topkegola). It is corticolous on Potentilla fruticosa, Rhododendron sp. etc. on high altitudes, 3200-4700 m.
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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