Pyxine dactyloschmidtii Kalb & Mongkolsuk, 2012

Mongkolsuk, Pachara, Meesim, Sanya, Poengsungnoen, Vasun & Kalb, Klaus, 2012, The lichen family Physciaceae in Thailand-I. The genus Pyxine, Phytotaxa 59 (1), pp. 32-54 : 44-45

9. Pyxine dactyloschmidtii Kalb & Mongkolsuk , sp. nov. ( Fig. 3B )

Mycobank MB 800693

Similar to Pyxine schmidtii Vain. (showing the same array of terpenes on TLC plates in solvent A, B' and C), but differing by having polysidiangia.

Holotype:— THAILAND. Loei; Phu Luang Wildlife Sanctuary, Khok Prommachan, Kok Nok Kraba Forest Ranger Station , in a lower montane scrub on an unidentified tree, 1487 m, 17°16'53'' N, 101°31'22'' E, 25 March 2009, S. Meesim 46 ( RAMK 17626 ).

Thallus corticolous, 4–10 cm wide, adnate to loosely adnate, subdichotomously lobate. Lobes radiating, discrete or rarely contiguous and imbricate, plane to distinctly convex but often slightly concave towards the tips, 0.7–1.2 mm wide, subrotund at the apices. Upper surface grey to whitish grey, epruinose, or very faintly pruinose towards the lobe tips; isidia and soralia absent. Pseudocyphellae sparse, marginal and laminal, irregular to linear or becoming finely reticulate. Polysidiangia mainly laminal, occasionally marginal, scattered or clustered, nodular to subcylindrical or clavate, short, ± branched, pustulate, bursting apically to release corticate fragments; simulating elevated soralia when abraded. Medulla uniformly white. Lower surface black in the centre, paler towards the margin; rhizines ± dense, furcate. Apothecia common, obscurascens - type, 0.5–1.8 mm wide; disc epruinose. Internal stipe distinct, white, K-, P-. Ascospores 16–20 × 6–8 µm. Pycnidia not seen.

Chemistry: Cortex K+ yellow, C-, KC-, P+ yellow, UV-; medulla K-, C-, P+ orange-red; containing atranorin (minor), chloroatranorin (minor), testacein (major), unknown terpenes (minor).

Distribution and habitat:—Very rare on bark in a lower montane scrub.

Notes:—This species is characterized by the adnate to loosely adnate thalli, the presence of polysidiangia, a white medulla, cortical atranorin, medullary testacein and obscurascens - type apothecia. P. coralligera , P. maculata Swinscow & Krog ( Swinscow & Krog 1975a: 58), P. subcoralligera (see below) and P. boonpragobiana are morphologically similar as all produce polysidiangia as vegetative propagules. While the first three species are distinguished by a coloured medulla, the latter is easily separated by the presence of norstictic acid. P. dactyloschmidtii shows the same array of terpenes as P. schmidtii and P. asiatica , but the former species lacks vegetative propagules while the latter has soralia.

Material from Thailand examined:— Known only from the type collection .

Figures

FIGURE 3. A. Pyxine boonpragobiana (hb. K. Kalb 36928), thallus with polysidiangia; Scale: 3 mm. B. Pyxine dactyloschmidtii (holotype), thallus with polysidiangia; Scale: 3 mm. C. Pyxine pseudoceralensis (holotype), thallus with isidia; Scale 2 mm. D. Pyxine subcoralligera (holotype), thallus with polysidiangia; Scale 3 mm. E. Pyxine cylindrica (hb. K. Kalb 36836), thallus with marginal and partly laminal isidia; Scale 2 mm. F. Pyxine cognata (hb. K. Kalb 12344), thallus with obscurascens-type apothecia and patchy priuna; Scale 3 mm.