Endocena

''Endocena'' is a genus of lichen-forming fungi in the family Icmadophilaceae. It has two species. ''Endocena'' is characterised by a thallus that can range from crustose to somewhat fruticose, with features such as hollow , , and granular . Apothecia, or sexual fruiting bodies, are rare and poorly developed. The three taxa within the genus have distinct distributional ranges, with ''Endocena informis'' var. ''informis'' being widely distributed in southern South America, while ''Endocena informis'' var. ''falklandica'' is common in the Falkland Islands, and ''Endocena buckii'' has a restricted range in Chilean Tierra del Fuego.

Taxonomy

The genus ''Endocena'' was established by the Scottish lichenologist James Mascall Morrison Crombie in 1876, based on a specimen collected on the west coast of Chile. The type species, ''Endocena informis'', was distinguished from '' Siphula'' by its hollow thallus structure. Crombie included this single species in the genus and highlighted its similarities to ''Siphula'' while noting the key difference of a hollow thallus. This relationship and the genus's placement within the family Icmadophilaceae were later confirmed by Stenroos and colleagues in 2002.

In examining the extensive lichen collections from southern South America, several collections from the Falkland Islands and Isla de los Estados were found to resemble ''E. informis'' but differed in being and having a thallus composed of flat to convex . These collections were chemically similar to ''E. informis'', both containing thamnolic acid. Further molecular studies aimed to confirm the placement of this new sorediate taxon within ''Endocena'', revealing that both it and ''E. informis'' were congeneric with the recently proposed genus ''Chirleja''. This new taxon was morphologically distinct but genetically similar, leading to the proposal to synonymise ''Chirleja'' under ''Endocena''.

Molecular data, including ITS and mitochondrial small subunit sequences, showed that members of ''Endocena'' and ''Chirleja'' form a supported monophyletic group within the Icmadophilaceae. Despite the genetic uniformity, significant morphological differences were observed among the taxa, leading to the recognition of distinct species and varieties within the genus. As a result, the genus ''Chirleja'' was synonymised under ''Endocena'', with ''Endocena buckii'' (formerly ''Chirleja buckii'') and ''Endocena informis'' var. ''falklandica'' (a sorediate taxon from the Falkland Islands) being formally recognised.

Description

The genus ''Endocena'' features a thallus that can range from (crust-like) to (somewhat shrub-like), composed of hollow or (stalk-like structures), or solid pseudopodetia with granular (leaf-like structures) on a thin in one species. The thallus may or may not have soredia (powdery reproductive structures). (asexual spore-producing structures) are present in one species.

Apothecia (sexual fruiting bodies) are very rare, poorly developed, (attached directly without a stalk), up to 2 mm in diameter, with irregular, strongly concave and (wavy) margins. The disc is pale pink-buff and no functional hymenium (spore-producing tissue) has been observed.

Chemically, ''Endocena'' contains thamnolic acid, as identified by thin-layer chromatography. Apothecia have been reported from four collections, two from ''E. informis'' var. ''falklandica'' and two from ''E. informis'' var. ''informis''. The apothecia start as with a white, surface that expands and becomes pinkish as the white granules disperse, eventually revealing the apothecium disc.

Habitat and distribution

''Endocena'' includes three taxa with distinct distributional ranges. ''Endocena informis'' var. ''informis'' is widely distributed throughout southern South America, from the Falkland Islands and Isla de los Estados to the southern regions of Chile, extending as far north as Región de los Lagos (42°S). It is rarely reported from Argentina, with only a few historical records. Despite this, it is frequently collected on Isla de los Estados and southern Isla Grande de Tierra del Fuego.

''Endocena informis'' var. ''falklandica'' is common in the Falkland Islands but less frequent in Tierra del Fuego, known from only two collections in Chile. ''Endocena buckii'' has an even more restricted range, with a single known collection from Seno Agostini in Chilean Tierra del Fuego.

There is a dubious report of ''E. informis'' from Macquarie Island, Australia, which lacks supporting herbarium specimens and is likely a misidentification of a similar species. The ecological preferences of these taxa vary, with both varieties of ''E. informis'' being terricolous and primarily found in open heathland. Variety ''informis'' typically grows among bryophytes, while var. ''falklandica'' is more frequent on soil and peat. The single collection of ''E. buckii'' was from the underside of a tree in a wet ''Nothofagus'' forest, though it may also inhabit soil-based environments.

Species

*'' Endocena buckii''
*'' Endocena informis''

References

{{Taxonbar, from=Q21223503

Pertusariales
Pertusariales genera
Lichen genera
Taxa described in 1876
Taxa named by James Mascall Morrison Crombie