Lichens marins - Peltigera venosa (L.) Hoffm.

Peltigera venosa (L.) Hoffm.

Synonyms:

Family: PELTIGERACEAE

Habitat: Montane

Description

Thallus foliose formed by a single lobe or 2-3 lobes of 5-20 mm arranged in a rosette 2-4 cm in diameter, relatively thick with rounded ends, upper surface smooth and shiny of a beautiful bright green by humid weather, gray-green in dry weather, underside whitish with large flattened veins arranged in a fan pattern, brownish, blackish-brown, on which some blackish globular cephalodia are arranged. Apothecia almost always present, arranged and as if posed towards the margin of the lobes, 1-6 per lobes, relatively sessile, 2-4 mm in diameter, disc flat to slightly domed, dark reddish-brown to blackish-brown, very fine margin, net. Asci in club, 100-120 x 20-28 µm according to our measurements, with 8 spores. Hyaline spores becoming slightly brownish, shuttle-shaped, 3-septate, 30-45 x 6-8 µm according to the literature, 32-45 x 6-8 µm according to our measurements. Primary photobiont; Coccomyxete, secondary photobiont; Nostoc-type cyanobacteria in cephalodia. No colored chemical reactions. Mountain and arctic species occuring to humid and mossy soils.

N.B. There are two morphotypes that can coexist:

Morphotype "blue-green" with an appearance of Scytinium lichenoides, which occurs in the form of small gray-brownish, gray-bluish, slightly gelatinous, 0.5-1 mm squamules formed by a network of filamentous hyphae retaining cells of a cyanobacterium (Nostoc). This morphotype goes completely unnoticed unless the "green" morphotype grows above or in the immediate vicinity, which is often the case.

Morphotype "green", with in addition a green alga, described above.