Sicut Malmidea polycampia (Tuck.) Kalb & Lücking sed ascosporis maioribus, soraliis deficientibus differt.

Type:— MASCARENE ISLANDS. Reunion: Forêt de Bébour, a few km NW of Plaine-des-Palmistes, sentier botanique, in a pristine tropical mountain rainforest, 1300 m, 21°08’ S, 55°35’30’’ E, 31 August 1991, K. & A. Kalb (holotype hb. Kalb 25202).

Etymology:—The new lichen is named after the island where the type was collected.

Thallus crustose, corticolous, continuous, 50–90 µm thick, minutely verrucose, soralia and isidia absent. Medulla of verrucae and thallus cream to yellowish, KOH+ orange to pale purple. Photobiont chlorococcoid, cells 5–7 µm diam. Apothecia sessile, rounded, 0.7–1.5 mm diam. and 0.4–0.5 mm high; disc plane to slightly convex, chocolate brown; margin of granifera - type, thin, entire, slightly prominent, depressed with age, cream coloured to pale yellow. Excipulum hyaline at periphery, internally with a medullary layer composed of loosely arranged, periclinal hyphae with constricted septa, 120–150 µm wide, incrusted with ochraceousyellow hydrophobic granules, dissolving in KOH with a lemon yellow reaction. Hypothecium 180–250 µm high, pale brown to honey brown, KOH-. Epihymenium indistinct. Hymenium 160–200 µm high, hyaline. Asci 90–110 × 20–25 µm, (2–)4(–8) spored. Ascospores non-septate, wall not uniformly thickened, i.e. distinctly thicker at the ends, halonate, ellipsoid to fusiform, 22–30 × 12–15 µ m, halo 1–1.5 µm wide. Chemistry: no atranorin detected, but at least 6 unknown lichen substances present, among them one major yellow pigment with relative R f -values 50, 34, 35 in solvents A, B’ and C (Elix & Ernst-Russell 1993).

Notes:—The new species is distinguished by the rather large ascospores with distinct, terminal wall thickenings. Similar ascospores are known from M. chrysostigma (Vain.) Kalb, Rivas Plata & Lumbsch and M. incrassata Kalb (see above). The former can be distinguished by its golden to orange-red medulla and the presence of emodin as a major metabolite while the latter is distinguished by a piperis - type exciple, the lack of thalline warts and the much smaller ascospores. From M. polycampia, it is distinguished by the absence of soralia.

Additional material examined: — MASCARENE ISLANDS. Reunion: Cirques de Cilaos; Mare à Joseph between Thermales and Bras Sec, in remnants of a pristine rainforest, 1350 m, 21°07’30’’ S, 55°30’ E, 24 August 1991, K. & A. Kalb (hb. Kalb 38967).