Malmidea inflata is a corticolous (bark-dwelling), crustose lichen in the family Malmideaceae. It was described in 2011 from northern Thailand; the species has a densely warted thallus and non-septate, ascospores, and it resembles M. aurigera but differs in having a whitish medulla rather than bright yellow in the thallus warts.
The species was introduced as Malmidea inflata 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, near Mae On east-south-east of Chiang Mai, in evergreen montane forest dominated by Lithocarpus, Quercus and Castanopsis at approximately mid-elevation. The specific epithet refers to the conspicuous thallus warts, which look like tiny inflated balloons.
The thallus is thin, crust-like and continuous (about 150âÂÂ200 üm thick) on bark, densely warted () with warts 0.2âÂÂ0.3 mm high and 0.2âÂÂ0.3 mm wide; soredia and isidia are absent. The medulla is whitish and reacts potassium hydroxide (KOH)-positive (orange). The is , with cells 5âÂÂ8 üm in diameter. Apothecia are , rounded and 0.7âÂÂ1 mm across and 0.3âÂÂ0.4 mm high; the is plane to slightly convex, dark brown to blackish, and bordered by a thin margin of the granifera type that is 20âÂÂ40 üm thick, initially entire and slightly prominent but tending to become recurved with age; the margin ranges from grey to dark brownish or blackish. The is hyaline at the periphery and internally shows a medullary layer with only a few hydrophobic granules that dissolve in KOH without a distinct colour reaction. The is about 10 üm high and olive-brown, the about 25 üm and dark brown, the hymenium 75âÂÂ100 üm and hyaline, and the 100âÂÂ170 üm and blackish-brown, with a Kâ reaction. Asci measure 65âÂÂ80 à10âÂÂ15 üm. Ascospores number 6âÂÂ8 (occasionally as few as 4) per ascus, are colourless, ellipsoid, non-septate and , 10âÂÂ13 (more rarely up to 17) à6âÂÂ8 üm with an approximately 1-üm . Reported chemistry includes atranorin (major) with several as-yet unidentified lichen substances (minor).
Known from northern Thailand, the species grows on tree bark in evergreen montane forest near the Doi Mon LarnâÂÂMae Kampong area east-south-east of Chiang Mai, where the canopy is dominated by Lithocarpus, Quercus and Castanopsis.