Pyrenula multicolorata Weerakoon & Aptroot, 2016

Weerakoon, Gothamie & Aptroot, André, 2016, Nine new lichen species and 64 new records from Sri Lanka, Phytotaxa 280 (2), pp. 152-162 : 158

Pyrenula multicolorata Weerakoon & Aptroot , sp. nov. ( Fig. 2H–J )

Mycobank No.: MB 817615

Pyrenula with ascomata almost superficial, low conical, 0.5–0.7 mm in diam.; hamathecium inspersed with many orange, KOH-negative crystals that are colouring the hamathecium red close to the wall and yellow in the centre; ascospores 3-septate, 12–13.5 × 4.5–5.5 μm.

Type: — SRI LANKA. Kitulgala-Makandawa, on bark of tree, 29 March 2015, G.Weerakoon Ki05 (holotype PD, isotypes ABL & F).

Thallus oily, olive green, quite thick, without pseudocyphellae, covering an area up to 5 cm diam., surrounded by a thin black hypothallus line. Ascomata almost superficial, low conical, simple or occasionally a few fused sideways, black, not covered by thallus, 0.5–0.7 mm in diam. Ostiole apical, brown to black. Hamathecium inspersed with many orange, KOH-negative crystals that are colouring the hamathecium red close to the wall and yellow in the centre. Ascospores 8/ascus, pale brown (dark brown only when postmature), irregularly biseriate, 3-septate, 12–13.5 × 4.5–5.5 μm, lumina becoming diamond-shaped, wall relatively thick, with a thick layer of endospore in the spore tips. Pycnidia not observed. Chemistry. Thallus UV–, K–. Hamathecium with orange to red or yellow (depending on dilution), KOHnegative substance. TLC: No substances detected.

Distribution and habitat: —On tree in wet lowland tropical rain forest. Only known from Sri Lanka.

Discussion: —This species is well characterized by the tiny orange crystals in the hamathecium that colours the hamathecium red where they are highly concentrated and yellow where they are diluted. Pyrenula species with coloured hamathecium were unknown until recently three neotropical species were described, P. rubroinspersa Aptroot & Sipman ( Aptroot et al. 2013: 188) with red, P. flavoinspersa Aptroot & Sipman ( Aptroot et al. 2013: 172) with yellow and P. aurantioinspersa Aptroot & Sipman ( Aptroot et al. 2013: 172) with orange hamathecium. However, all these species have larger (the orange inspersed one over 60 μm long) ascospores and the colour is in oil, not in crystals. Moreover, in two of these three species, the oil turns green in KOH.

Figures

FIGURE 2. A–B, Porina microtriseptata, A, habitus, B, ascospores; C–D, Porina monilisidiata, C, habitus, D, ascospores; E–G, Psoroglaena spinosa, E, habitus, F–G, detail; H–J, Pyrenula multicolorata, H, habitus with sectioned ascoma, I, hamathecium, J, ascospores; K–N, Schistophoron muriforme, K, habitus, L, section through ascoma showing mazaedium, M–N, ascospores. Scale: A, D, H = 0.5 mm, B, M, N = 20 μm, E, K, L = 0.25 mm, F–G = 50 μm, I–J = 25 μm.