Rinodina riparia Sheard (1988: 37)

Galanina, Irina A., Kharpukhaeva, Tatyana M. & Poryadina, Lena N., 2024, Rinodina riparia (Physciaceae, lichenized Ascomycota) new to Eurasia from China and Russia, Phytotaxa 652 (2), pp. 165-170 : 166-168

Rinodina riparia Sheard (1988: 37)

Type:— U.S.A. Colorado. Jefferson Co., alongside Deer Creek, 4.7 km W of junction of Colo. 470 and Deer Creek Road. Growing at base of Populus angustifolia, 1650 m a.s.l., 5. V 1974, M.B. Carmer 2525 ( COLO — holotype, SASK — isotype, Sheard, 2010).

( Figs 2A–C )

Thallus thin, areoles at first discrete and slightly convex 0.2–0.5 mm wide, to 0.5–0.6 mm wide in older parts, light to dark gray sometimes with a brownish tinge. Prothallus and vegetative propagules absent.

Apothecia numerous, broadly attached and densely contiguous in older parts of the thallus ( Fig. 2 : A), 0.4–0.6 (–1.0) mm diameter (n = 18); disc black, persistently plane; thalline margin concolorous with thallus, entire and persistent; confluent excipular ring sometimes present. Сortex of apothecia to 20 μm wide, not expanded below. Proper exciple hyaline, 15 μm wide, expanding to 20 μm at surface, pigmented the same colour as epihymenium; hypothecium hyaline, 30–40 μm high; hymenium 70–100 μm high, paraphyses 1.5–2.0 μm wide, not conglutinate, apices to 5.5–6.8 μm wide, forming a red-brown epihymenium. Ascospores 8 per ascus, type B development, Dirinaria - type ( Fig. 2 : B, C, D), (18.0–) 21.5–22.5 (–27.5) × (9.0–) 10.0–11.0 (–12.0) μm (n = 49), with Physcia -like lumina during development, torus lacking, septal disc sometimes present, walls rarely ornamented. Most mature spores inflated at septum, more so on application of KOH. Spores have lightly pigmented bulbous, apices at maturity (described as being “almost mucronate” by Sheard 1998).

Pycnidia not seen.

Chemistry: Spot tests all negative.

Distribution: Rinodina riparia is reported as new to Eurasia from China and Russia ( Fig. 1 ). In China, it was found in the Nanshan Highlands. In Russia, the species was found in Yakutia (Yakutsk vicinity) and Buryatia (Dzherginsky Reserve). The species was first described from Northern America (Colorado) by Sheard (1998). Its distribution in North America was supplemented by new location from North Dakota ( Sheard, 2018). R. riparia was thought to be endemic to the continent, possessing a north-south distribution mainly east of the Rocky Mountains ( Sheard, 2010).

Specimens examined: CHINA, Nanshan Highlands, on bark, 1885–1886 (collection date unknown), G.N. Potanin, LE 25792 ; RUSSIA, Republic of Buryatia, Kurumkansky District, Dzherginsky Reserve , Ikatsky Ridge , upper reaches of Barguzin River , Turakina stream valley, old fire-site, 55°20′26.6″N, 111°30′02″E, 1097 m a. s. l., on plant debris, 06 VII 2001, T. M. Kharpukhaeva, UUH L-02947 ; Republic of Sakha (Yakutia), Yakutsk vicinity, 33 km of highway P-503 to Kildemtsy , top of the slope, 62°16′19.2″N, 129°50′33″E, 95 m a. s. l., flat steppe area surrounded by larch forest, on wood partly buried in sand, L.N. Poryadina, SASY L- 2008-08-07 /0-2 .

Figures

FIGURE 1. Distribution of Rinodina riparia in Eurasia and North America.

FIGURE 2. Rinodina riparia (specimen fromYakutia, SASY L-2008-08-07/0-2).A. Habit of Rinodina riparia, apothecia broadly attached and contiguous, disc persistently plane, thalline margin concolorous with thallus, entire and persistent. B, C. Dirinaria-type spores with the Physcia-like lumina. B. Premature spore, note the septal swelling and lack of a torus. C. Mature spores showing bulbous apices and septal swelling in KOH. D. Immature spores indicate prior to septal division in Type B development in KOH. Scale: A = 0.5 mm, B, C, D = 10 μm.