Malmidea perplexa
Malmidea perplexa is a corticolous, crustose lichen in the family Malmideaceae. It was described in 2011 from northern Thailand. The species has a smooth, grey-green thallus without warts and ascospores that are non-septate and. It resembles Malmidea leptoloma but differs in having lighter-coloured apothecial discs and margins and a smooth thallus.Taxonomy
The species was introduced as Malmidea perplexa by Klaus Kalb in 2011 within a study on Malmidea and the family Malmideaceae. The holotype was collected on the descent from Doi Mon Larn to Mae Kampong village, east-south-east of Chiang Mai, in evergreen montane forest dominated by Lithocarpus, Quercus and Castanopsis; the specific epithet reflects that the senior author had known the species from Brazil for decades before finding it in Thailand again.Description
The thallus is crust-like, continuous and smooth, about 100–250 μm thick, dull to slightly shiny and grey-green; soredia and isidia are absent. The medulla is whitish and K–. The is with cells 6–8 μm in diameter. Apothecia are, rounded, 0.4–0.7 mm across and 150–180 μm high; the is plane to slightly convex and brown-grey to sooty, bordered by a thin margin of the piperis type that is about 20 μm thick, slightly prominent and whitish-grey to dark brownish-grey. The is hyaline and internally lacks the medullary layer and lacks hydrophobic granules; the is about 20 μm high and light brown, the hymenium 75–120 μm and hyaline, and the 30–80 μm and hyaline, K–; the is indistinct. Asci measure 50–65 × 10–15 μm. Ascospores number 6–8 per ascus, are colourless, ellipsoid, non-septate and, 9–13 × 5–7 μm with an about 0.5-μm. No lichen substances were detected by thin-layer chromatography or high-performance liquid chromatography.Habitat and distribution
The species grows on tree bark in evergreen forests in Thailand and is also recorded from south-eastern Brazil, at roughly 520–1000 m elevation.