Chapsa

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 . Its ascomata are : they start as slits but expand into round to angular discs level with the thallus, each bordered by a pale, partly free armed with tiny . 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 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 • Chapsa alborosella • Chapsa alletii • Chapsa angustispora • Chapsa boninensis • CChapsa canaimae • Chapsa chionostoma • Chapsa cinchonarum • Chapsa constrictospora – Brazil • Chapsa defecta • Chapsa defectosorediata • Chapsa diorygmoides – Brazil • Chapsa diploschistoides • Chapsa discoides • Chapsa dissuta • Chapsa eitenii • Chapsa elabens • Chapsa farinosa • Chapsa francisci • Chapsa granulifera • Chapsa halei • Chapsa hiata • Chapsa hypoconstictica • Chapsa imperfecta • Chapsa inconspicua – Colombia • Chapsa indica • Chapsa inspersa – Brazil • Chapsa isidiata • Chapsa laemensis • Chapsa leprocarpa • Chapsa lichexanthonica – Brazil • Chapsa meghalayensis • Chapsa microspora • Chapsa multicarpa • Chapsa neei • Chapsa niveocarpa • Chapsa nubila • Chapsa pallidella • Chapsa paralbida • Chapsa patens • Chapsa perdissuta • Chapsa pulchella • Chapsa pulchra • Chapsa referta • Chapsa rubropruinosa • Chapsa rubropulveracea • Chapsa scabiocarpa – Peru • Chapsa scabiomarginata • Chapsa sorediata • Chapsa sublilacina • Chapsa subsorediata – Peru • Chapsa thallotrema • Chapsa thambapanni – Sri Lanka • Chapsa tibellii • Chapsa wijeyaratniana ==References==