Malmidea hechicerae

Malmidea hechicerae is a species of corticolous (bark-dwelling), crustose lichen in the family Malmideaceae. It is found in Venezuela.

Taxonomy
The lichen was formally described as a new species in 2021 by the German lichenologist Klaus Kalb. The type specimen was collected from Monte Zerpa (Distr. Libertador, Mérida) at an elevation of 2200 m, where it was found growing in a cloud forest. The species epithet refers to its type locality, known as La Hechicera.

Description
Malmidea hechicerae is a crustose lichen with a continuous thallus that is 40–60 μm thick. The thallus surface is, with the being more or less spherical and measuring 0.1–0.25 mm in diameter. These verrucae have a dull, whitish-grey appearance. The species lacks both soralia and isidia (reproductive propagules). The medulla of the verrucae and thallus is white, reacting K+ (lemon-yellow), occasionally showing a slightly orange-yellow hue, and P+ (orange), best observed in sections under a light microscope.

The of Malmidea hechicerae is  with cells measuring 6–8 μm in diameter. The apothecia are sessile and rounded, ranging from 0.6–1.3 mm in diameter and 0.3–0.4 mm in height. The of the apothecia are more or less flat and vary in colour from beige to brownish or dark brown. The is of the granifera-type, remaining, and is whitish to cream-coloured, bulging, and elevated above the disc. The is hyaline (translucent) to brownish, particularly at the edges, while the medullary excipulum is filled with colourless opaque  that partly dissolve in potassium hydroxide, producing a greenish-yellow efflux.

The of the lichen is roughly 20 μm high and light brown, with a centrally located  measuring 50–70 μm high that narrows towards the margin and is dark brown, not reacting to K. The  is light brown, and the hymenium is hyaline, measuring 70–80 μm in height. The asci are 55–65 μm long and 8–15 μm wide, each containing 6 to 8 that lack septa. These ascospores are broadly ellipsoid, with equally thickened and walls, measuring 13–17 by 7–9 μm, and are surrounded by a  of 1–1.5 μm.

In terms of chemistry, Malmidea hechicerae is characterized by several xantholepinone substances, detectable using thin-layer chromatography. Atranorin is not detected in this species. Malmidea coralliformis similar in appearance to M. hechicerae but has a different set of xantholepinones.