Ramonia minima J. Kalb & Kalb, 2017

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 : 152

Ramonia minima J. Kalb & Kalb , sp. nov. ( Figs. 3B, 3C )

Mycobank MB823631 Similar to R. kandleri Kalb , but differs in having smaller apothecia, a lower hymenium and a partly brown to blackish exciple. Type:— THAILAND. Ratchaburi province: Suan Phueng district ; tambon Suan Phueng, trail to Kaew Chan Waterfall (Nine-Level

Waterfall), bamboo scrub with scattered deciduous trees along a creek (mixed deciduous forest), 200–250 m, 13°31’31’’ N, 99°14’23’’

E, 11 December 2015, J. Sutjaritturakan & K. Kalb 41276 (RAMK, holotype).

Etymology:—The species name refers to the very small apothecia.

Thallus corticolous, crustose, grey, thin, smooth, ecorticate, dull, up to 1.5 cm in diam. Photobiont trentepohlioid, cells ± spherical, ca. 7–10 μm in diam. Apothecia scattered, pale flesh-coloured, globular, 0.1–0.2 mm in diam., at first immersed in the thallus and substrate, later erumpent and semi-immersed; ostiole roundish, 25–50 μm in diam., with a star-like margin composed of 6–10 recurved, white triangular lobules. Exciple paraplectenchymatous, inner part hyaline, outer part brownish to brownish black, 30–50 μm thick, upper part with 10–25 μm long periphyses ( Fig. 3C ). Hymenium clear (not inspersed), hyaline, 90–110 μm high. Paraphyses unbranched, 2–2.5 μm thick, endcell up to 3 μm thick. Asci clavate, 65–80 × 10–15 μm with 32–64 ascospores; ascospores hyaline, non-septate, broadly ellipsoid to narrowly ellipsoid or drop-shaped ( Fig. 3C ), 6–9 × 3–5 μm (excluding halo), halonate, halo 1–2 μm thick. Pycnidia not seen.

Distribution and habitat:— Thailand. At present known from the type locality, where R. minima grows on bark of a deciduous tree in a mixed deciduous forest between 200– 300 m. Growing together are Coenogonium verrucimarginatum J. Kalb & Kalb ( Kalb et al. 2016) and Bacidia medialis (Tuck.) Zahlbr. A photograph of the typelocality is published in Kalb et al. (2016: 103, Fig. 2 ).

Remarks:—With the partly dark exciple, the ellipsoid to ovoid spores and the star-like margin of the ostiole, R. minima is intermediate between section Ramonia (type species R. valenzueliana ) and section Gyalenidium (type species R. malmei ) as distinguished by Vězda (1966). There are only two species known with non-septate ascospores broader than 3 μm, viz. R. intermedia Kalb and R. kandleri Kalb ( Kalb 1983; Aptroot et al. 2015). R. minima can be distinguished from R. intermedia by its larger ascospores (4–6 × 3 μm in R. intermedia ) and from R. kandleri by the smaller apothecia (0.2–0.6 mm in R. kandleri ), lower hymenium (200 μm high in R. kandleri ) and a partly brown to blackish exciple (hyaline in R. kandleri ).

The genus Ramonia is a new addition to the Thai lichen biota.

Figures

FIGURE 2. A. Graphis indica (J.K. & K.K, KJK 41769; scale 1 mm); B. Leucodecton occultum (J.K. & K.K, KJK 41952; scale 0.25 mm); C. Phaeographopsis palaeotropica, ascomata with a distinct black mazaedium (J.K. & K.K, KJK 41398; scale 0.5 mm); D. Phaeographopsis palaeotropica, ascomata lacking a mazaedium (J.K. & K.K, KJK 41395; scale 0.4 mm); E. Platygramme australis (J.K. & K.K, KJK 41279; scale 0.5 mm); F. Platygramme commutabilis (Sutjaritturakan 4225, KJK 42227; scale 1 mm); G. Platygramme discurrens (Sutjaritturakan 4895, KJK 42217; scale 0.3 mm); H. Platygramme subcolubrosa (J.S. & K.K., KK 41534; scale 0.5 mm).

FIGURE 3. A. Pseudotopeliopsis longispora (J.K. & K.K, KJK 41893; scale 0.5 mm); B. Ramonia minima, ascomata (holotype; scale 0.2 mm); C. Ramonia minima, section through ascoma (scale 25 μm; inlay, ascospores (scale 5 μm); D. Sclerophyton seriale (J.K. & K.K, KJK 42013; scale 1 mm); E. Traponora macrospora (K.K. et al., KK 36844; scale 0.2 mm); F. Trinathotrema stictideum (Vongshewarat s.n. RAMK; scale 0.3 mm).