Leptogium menziesii
Leptogium menziesii is a species of jelly lichen in the family Collemataceae. This dark, foliose lichen typically forms broad, overlapping with a felted, beard-like underside of hairs. Its thallus and fruiting rims are unornamented, and the bases of the discs and the tiny asexual structures are hairy; these features help separate it from similar Antarctic and subantarctic species. It is chiefly a subantarctic species, with records from southern South America and several southern hemisphere islands.
Taxonomy
The species was first brought into print in Erik Acharius's Methodus, where it appears under his collematoid section. Acharius placed it in Parmelia and at the same time credited James Edward Smith's manuscript name "Lichen Menziesii D. D. Smith. Msc.". He gave a brief Latin of a gelatinous, somewhat membranous, brownish-green thallus, white- beneath, with rounded, plane lobes and red,, bell-shaped apothecia, and recorded the habitat as the Strait of Magellan based on collections by Archibald Menzies. Acharius later transferred the species to Collema as Collema menziesii. The currently accepted combination, Leptogium menziesii, was published by Camille Montagne in 1852. The type material was collected by Menzies on Staten Island near Cape Horn in February 1789; in 1975 Per Magnus Jørgensen designated a neotype from this gathering, which is preserved in the herbarium of the Royal Botanic Garden Edinburgh.Description
The thallus is about 7 cm across and 50–75 micrometres thick, brownish-grey in fluorescent light and greenish-grey under a stereomicroscope. Lobes are broad, overlapping and appressed; their tips are rounded and smooth, and the margins are thin and even. Isidia and are absent. Attachment is by abundant simple hairs that become "beard-like" as they agglutinate; the lower surface is . The upper is a single layer of brick-like cells; the lower cortex is likewise single-layered and felted. In section, the medulla shows the fungal hyphae compactly woven with the cyanobacteria; columnar hyphae were not seen in the studied material, although the authors caution that rapid drying may have obscured them.Fruiting bodies of L. menziesii are small, and short-stalked. The apothecial discs are concave and their margins smooth to slightly wrinkled, without any or warting. The apothecial wall lacks a ; the is built of elongated cells, whereas the parahymenial tissue is brick-like. Ascospores were not observed in the material examined; in earlier work they were reported as having dimensions of 22–27 × 8–10 μm. Pycnidia occur on the thallus, usually near the margin, producing slender conidia about 3.75 × 1.25 μm. The bases of both apothecia and pycnidia are covered by hairs.