Bacidia Entocosmensis

''Bacidia'' is a genus of lichen-forming fungi in the family Ramalinaceae.

Taxonomy

The genus was circumscribed by Giuseppe De Notaris in 1846.

Description

''Bacidia'' is characterised by its crustose (crust-like) growth form. The main body (thallus) of these lichens typically appears as a thin layer that can be smooth, cracked, warty, or in texture. The thallus may sometimes develop specialised structures such as soredia (powdery propagules), isidia (small outgrowths), or tiny scale-like features. Its colour usually ranges from whitish to pale green, greenish-grey, pale grey, or fawn.

Like all lichens, ''Bacidia'' species represent a symbiotic partnership with algae. Their (algal partner) belongs to the group, featuring spherical or broadly oval-shaped cells. The fungal component produces distinctive reproductive structures called apothecia, which are disc-shaped and typically measure up to 1 mm across (occasionally reaching 1.3 mm). These apothecia sit directly on the thallus surface and can vary from flat to strongly convex in shape and come in various colours.

The internal structure of the apothecia is diagnostic for the genus. They lack a (an outer layer containing algal cells) but possess a – a protective layer composed of tightly packed, thick-walled fungal threads (hyphae) that have narrow internal channels and become gel-like. When stained with iodine, the spore-producing layer (hymenium) turns blue. Within this layer are specialised cells called paraphyses, which are rarely branched and often have swollen tips.

The spore-producing cells ( asci) are club-shaped to cylindrical-club-shaped and each contains eight . The spores themselves are colourless and typically long and narrow ( to needle-like) or S-shaped, though some species produce more cylindrical to spindle-shaped spores. These spores usually have three or more cross-walls (septa) when mature.

The genus also produces asexual reproductive structures called pycnidia, which can be sunken into or sitting on the thallus surface. These structures produce colourless spores (conidia) of various shapes, which may sometimes have cross-walls. When tested with common chemical spot tests used in lichen identification, the thallus shows no reaction, though the reproductive structures may contain various pigments.

Species

*'' Bacidia absistens''
*'' Bacidia albogranulosa''
*'' Bacidia alutacea''
*'' Bacidia arceutina''
*'' Bacidia areolata'' – Russian Far East
*'' Bacidia beckhausii''
*'' Bacidia biatorina''
*'' Bacidia brigitteae'' – Kangaroo Island
*'' Bacidia caesiovirens'' – western Europe
*'' Bacidia campbelliae''
*'' Bacidia carneoglauca''
*'' Bacidia chrysocolla''
*'' Bacidia circumspecta''
*'' Bacidia conspicua''
*'' Bacidia convexa''
*'' Bacidia cornea''
*'' Bacidia coruscans''
*'' Bacidia curvispora''
*'' Bacidia cylindrophora''
*''Bacidia depriestiana''
*'' Bacidia effusa''
*'' Bacidia ekmaniana''
*'' Bacidia elongata'' – Russian Far East
*'' Bacidia entocosmensis''
*'' Bacidia entodiaphana''
*'' Bacidia fellhaneroides''
*'' Bacidia fluminensis''
*'' Bacidia fratruelis''
*'' Bacidia friesiana''
*'' Bacidia furfurella''
*'' Bacidia fuscoviridis''
*'' Bacidia gallowayi''
*'' Bacidia granosa''
*'' Bacidia gullahgeechee'' – United States
*'' Bacidia heterochroa''
*'' Bacidia herbarum''
*'' Bacidia iberica'' – Spain
*'' Bacidia johnstoniae''
*'' Bacidia kekesiana''
*'' Bacidia killiasii''
*'' Bacidia kurilensis'' – Russian Far East
*'' Bacidia laurocerasi''
*'' Bacidia leucocarpa''
*'' Bacidia lithophila'' – Australia
*'' Bacidia littoralis'' – Australia
*'' Bacidia lividofusca''
*'' Bacidia lividonigrans''
*'' Bacidia lobarica'' – United States
*'' Bacidia maccarthyi'' – Australia
*'' Bacidia macquariensis''
*'' Bacidia macrospora''
*'' Bacidia marina'' – Falkland Islands
*'' Bacidia microphyllina''
*'' Bacidia millegrana''
*'' Bacidia modestula''
*'' Bacidia multicarpa''
*'' Bacidia multiseptata''
*'' Bacidia pallida''
*'' Bacidia paramedialis''
*'' Bacidia phyllopsoropsis''
*'' Bacidia placodioides''
*'' Bacidia polychroa''
*'' Bacidia prasinata''
*'' Bacidia pruinata'' – Falkland Islands
*'' Bacidia punica''
*'' Bacidia purpurans''
*'' Bacidia pycnidiata'' – central Europe
*'' Bacidia quadrilocularis''
*'' Bacidia raffii''
*'' Bacidia rhodocardia''
*'' Bacidia rosella''
*''Bacidia rosellizans''
*'' Bacidia rubella''
*'' Bacidia rudis''
*'' Bacidia sachalinensis'' – Russian Far East
*'' Bacidia schweinitzii''
*'' Bacidia scopulicola''
*'' Bacidia septosior''
*'' Bacidia sigmospora''
*'' Bacidia sipmanii''
*'' Bacidia sorediata''
*'' Bacidia squamellosa''
*'' Bacidia subareolata''
*'' Bacidia subproposita''
*'' Bacidia subturgidula''
*'' Bacidia superbula''
*'' Bacidia superula''
*'' Bacidia surinamensis''
*'' Bacidia termitophila''
*'' Bacidia thiersiana'' – United States
*'' Bacidia thyrrenica''
*'' Bacidia vagula''
*'' Bacidia vallatula''
*'' Bacidia veneta''
*'' Bacidia vinicolor''
*'' Bacidia viridescens''

References

Gallery

Image:Bacidia schweinitzii-8.jpg, Cross section of an apothecium of ''B. schweinitzii'', photographed through a compound microscope (x1000), showing a green epihymenium and a dark reddish-brown hypothecium
Image:Bacidia schweinitzii-7.jpg, Acicular spore of ''B. schweinitzii'', 65 x 6 micrometres, photographed through a compound microscope, x1000

{{Authority control

Ramalinaceae
Lichen genera
Lecanorales genera
Taxa named by Giuseppe De Notaris
Taxa described in 1846