Chapsa

Chapsa is a genus of lichens in the family Graphidaceae. These lichens form thin, grey-whitish to pale olive crusts on tree bark and are characterized by fruiting bodies that start as slits but expand into round to angular discs level with the surface, each bordered by a pale rim. The genus has a pantropical to warm-temperate distribution, growing on shaded bark in humid lowland or foothill rainforests, with over 60 species that often serve as indicators of undisturbed forest habitats.

Taxonomy

The genus was circumscribed by the Italian lichenologist Abramo Bartolommeo Massalongo in 1860. The genus was resurrected by Frisch and colleagues in 2006 to include species earlier classified in Chroodiscus, Myriotrema, Ocellularia, and Thelotrema.

Description

Chapsa forms a thin, grey-whitish to pale olive crust (thallus) lacking a true Template:Lichengloss. Its ascomata are Template:Lichengloss: they start as slits but expand into round to angular discs level with the thallus, each bordered by a pale, partly free Template:Lichengloss armed with tiny Template:Lichengloss. The clear hymenium has branched "Chapsa-type" paraphyses, is iodine-negative (I–), and houses eight hyaline ascospores that are transversely 3–15-septate; a few species develop longer, somewhat Template:Lichengloss spores. Most lack secondary metabolites, though some produce norstictic acid or stictic acid that tint the discs orange-brown.

Molecular work has split off allied genera (e.g., Astrochapsa, Pseudochapsa, Nitidochapsa) for lineages with divergent chemistries or spores, yet all share the chroodiscoid discs, periphysoids and branched paraphyses diagnostic for the group. Over 60 species remain in Chapsa, and discoveries such as C. murioelongata show that diversity is still being revealed.

Ecology

Chapsa has a pantropical to warm-temperate distribution, growing on shaded bark below about 1000 m elevation in humid lowland or foothill rainforests; some species extend into montane cloud forests above 2000 m. Its preference for moist, mature forest canopies means several species serve as indicators of undisturbed habitat, and surveys in China, Brazil and India continue to uncover narrowly endemic taxa.

Species

• Chapsa albida Template:Au
• Chapsa alborosella Template:Au
• Chapsa alletii Template:Au
• Chapsa angustispora Template:Au
• Chapsa boninensis Template:Au

• CChapsa canaimae Template:Au
• Chapsa chionostoma Template:Au
• Chapsa cinchonarum Template:Au
• Chapsa constrictospora Template:Au – Brazil
• Chapsa defecta Template:Au
• Chapsa defectosorediata Template:Au
• Chapsa diorygmoides Template:Au – Brazil
• Chapsa diploschistoides Template:Au
• Chapsa discoides Template:Au
• Chapsa dissuta Template:Au
• Chapsa eitenii Template:Au
• Chapsa elabens Template:Au
• Chapsa farinosa Template:Au
• Chapsa francisci Template:Au
• Chapsa granulifera Template:Au
• Chapsa halei Template:Au
• Chapsa hiata Template:Au
• Chapsa hypoconstictica Template:Au
• Chapsa imperfecta Template:Au
• Chapsa inconspicua Template:Au – Colombia
• Chapsa indica Template:Au
• Chapsa inspersa Template:Au – Brazil
• Chapsa isidiata Template:Au
• Chapsa laemensis Template:Au
• Chapsa leprocarpa Template:Au
• Chapsa lichexanthonica Template:Au – Brazil
• Chapsa meghalayensis Template:Au
• Chapsa microspora Template:Au
• Chapsa multicarpa Template:Au
• Chapsa neei Template:Au
• Chapsa niveocarpa Template:Au
• Chapsa nubila Template:Au
• Chapsa pallidella Template:Au
• Chapsa paralbida Template:Au
• Chapsa patens Template:Au
• Chapsa perdissuta Template:Au
• Chapsa pulchella Template:Au
• Chapsa pulchra Template:Au
• Chapsa referta Template:Au
• Chapsa rubropruinosa Template:Au
• Chapsa rubropulveracea Template:Au
• Chapsa scabiocarpa Template:Au – Peru
• Chapsa scabiomarginata Template:Au
• Chapsa sorediata Template:Au
• Chapsa sublilacina Template:Au
• Chapsa subsorediata Template:Au – Peru
• Chapsa thallotrema Template:Au
• Chapsa thambapanni Template:Au – Sri Lanka
• Chapsa tibellii Template:Au
• Chapsa wijeyaratniana Template:Au