Acanthothecis consocians ( Nylander 1868: 116 ) Staiger & Kalb (2000

Kalb, Jutarat & Kalb, Klaus, 2017, New lichen species from Thailand, new combinations and new additions to the Thai lichen biota, Phytotaxa 332 (2), pp. 141-156 : 142-144

Acanthothecis consocians ( Nylander 1868: 116) Staiger & Kalb (2000 [1999]: 97). ( Fig. 1A )

This species is characterized by its whitish to yellowish thallus, transversely 5–8-septate ascospores, 13–18 × 4–5 μm, I– and especially by its white lirellae containing psoromic acid (major) and 2‘- O -demethylpsoromic acid (minor to trace).

Distribution and habitat:— A. consocians is reported from India, Malesia and here from Thailand where it is growing on the bark of various deciduous trees in ± open but humid situations from 20– 700 m.

Material examined from Thailand:— Chiang Mai province: Doi Suthep-Pui National Park ; trail to Monthathan waterfall in a humid Dipterocarpus forest, 700 m, 18°49’00’’ N, 98°55’28’’ E, 17 March 2008, K. Kalb et al. 37067 (hb. K. Kalb)— Phetchaburi province: Kaeng Krachan district, road from Ban Krang Camp to ‘Stream 1’, in a humid secondary rainforest along a creek, 340 m, 12°48’ N, 99°26’ E, 8 December 2015, J. Sutjaritturakan & K. Kalb 41267 (Hb. K. & J. Kalb)— Chumphon province: Lang Suan district ; tambon Tha Maphla, in the area of Radburana Temple, in a butterfly tree ( Bauhinia purpurea ) plantation, 20 m, 09°56’24” N, 99°02’26” E, 17 May 2009, J. Sutjaritturakan 2671, 2672 (Hb. K. & J. Kalb) .

Remarks:—Only one Acanthothecis species, viz. A. salazinica S. Joshi & Hur in Joshi et al. 2013: 600, published on 23 August 2013) is mentioned in Buaruang et al. (2017). This name however is a later homonym of A. salazinica van den Boom & Sipman (2013: 12 , published on 30 June 2013). Subsequently, the error was recently corrected by Joshi et al. (2017: 264) where the illegitimate name was replaced by A. yokdonensis S. Joshi & Hur. The latter species is readily differentiated from A. consocians by the larger and more septate ascospores (27–29-septate, 70–120 × 7–14 μm) and the chemistry (salazinic acid).

Makhija & Adawadkar (2007) questioned the occurrence of psoromic acid in A. consocians . And indeed, it is not present in the thallus, but it is definitely present in the ascomata of this species, including the holotype which we have studied. This substance could be detected with TLC methods as well as with the spot test, P+ yellow.

A. consocians is a new addition to the Thai lichen biota.

Figures

FIGURE 1. A. Acanthothecis consocians (J.S. & K.K., KK37067; scale 0.5 mm); B. Caloplaca bassiae (J.K. & K.K, KJK 41911; scale 0.4 mm); C. Chapsa pulchra (K.K. et al., KK 39153; scale 0.5 mm); D. Constrictolumina leucostoma (K.K. et al., KK 40863; scale 0.5 mm); E. Allographa stictilabiata, section through ascoma showing the striate exciple (scale 100 μm); F. Allographa stictilabiata (K.K. & Poengsungnoen, KK 38768; scale 1 mm); G. Graphis aphaneomicrospora (K.K. et al., KK 38387; scale 0.8 mm); H. Graphis balaghatensis (J.S. & K.K., KJK 41380; scale 0.5 mm).