Gyalecta jenensis (Batsch) Zahlbr. var. jenensis

    Thallus crustose, thin and inconspicuous, without distinct margin, continuous to slightly cracked, dirty whitish, pale gray, pale greenish-gray, sometimes with pink or orange tinge. Apothecia up to 1 mm diam., globose, then, when opened with a pale orange disc, margin thick, crenulate, pale cream-orange (flower-like). Ascospores broadly ellipsoid, 3-septate becoming muriform, according to the literature: 12-25 x 6-10 µm (30-40 x 10-16 µm in the variety macrospora but the latter is doubtful because there are all the intermediate sizes of spores between these 2 varieties, see: Gyalecta jenensis forma), according to our own measurements: 20-25 (26) x (10) 12-14 (17) µm. Photobiont: Trentepohlia. Chemical spot tests negative, but sometimes K + pale yellow-orange by reaction of Trentepohlia. Usually on damp shady hard limestones and consequently rather rare in our prospection area.  However in our region Gyalecta jenensis var. macrospora  may be found on weakly acid rocks near the seashore or on damp shaded old walls with stones and mortar. N.B. Evokes small orange jam tartlets.

This species is very variable according to its habitat, in particular the thallus and the size of the spores, it is therefore possible, for the moment, to consider a single very variable species or then several varieties or forms, some of which are exposed here:

Gyalecta jenensis var. jenensis (Batch) Zahlbr. : Relatively small spores of 12-25 x 6-10 µm, everywhere on limestone rocks.

Gyalecta jenensis var. macrospora  Vezda: Relatively large spores 30-40 x 10-16 µm, near the sea on not too acidic rocks.

Gyalecta jenensis var. macrospora forma: Relatively large spores, 25-37 x 11-15 µm, thallus absent or formed by a layer of free cyanobacteria or Trentepohlia. On micaschists or granite by the sea.

Gyalecta jenensis forma: Spores of an intermediate size: 24-30 x 10-15 µm. On limestone blocks on the ground in the aerohaline zone.