476 A. Engler, Beiträge zur Flora von Afrika. LIT. 
Britisch-Ostafrika: Mombessa beim Portugiesenfort, auf Plumiera 
(Schröder n. 341). 
Arthonia angulata Fée, Suppl. Cryptog. Ecore. Officin., 1837, p. 39, 
tab. XL, fig. 9; A. Zahlbr., Catal. Lich., vol. II, p. 9. 
Kapland: Port Elizabeth, Baakens River Valley, auf Baumzweigen 
BRUNNTHALER). 
Arthothelium macrothecum Mass., Ricerch. Anton. Lich. Crost., 1859, 
p. 55; A. Zahlbr., Catal. Lich., vol. II, p. 128. — Arthonia macrotheca 
Fée, Suppl. Essai Cryptog. Ecorc. Offiein., 1837, p. 42, tab. XL, fig. 18, 
Ost-Usambara: Amani, auf Baumrinden (Schröner n. 188). 
Opegrapha prosodea Ach., Method. Lich., 1803, p. 22; A. Zahlbr, 
Catal. Lich., vol. IT, p. 232. 
Britisch-Ostafrika: Urwald bei Entebbe, auf Baumrinden (ScHRÖDER 
n. 330). 
Opegrapha (sect. Euopegrapha) exornata A. Zahlbr. in Annal. Myco- 
log., vol. XIX. (1924) p. 226. — Thallus epilithicus, tartareus, pallide aluta- 
ceus, opacus, KHO lutescens, CaCl,0: —, crustaceus, radiatim crescens, 
subplacodiiformis, plagas plus minus dispersas, irregulares vel vittaeformes 
et involutas formans, tenuis, usque 1 mm altus, in centro stalactizans, in- 
terruptus, versus marginem anguste albescens et in ipso margine tenuis- 
sime nigricanti-cinctus, sorediis nullis, cortice distincto non praeditus; go- 
nidia chroolepoidea, in parte superiore thalli sita, cellulis concatenatis, 
5—8 p latis, e rotundato subdifformibus, membrana tenui cinctis; hyphae 
thalli dense contextae, intricatae, tenuissimae, inspersae, hyphae ultimae 
elongatae, laxe ramosae vel subsimplices, verticaliter in substratum pene- 
trantes, ad 2 u crassae, increbrae septatae, membrana modice crassa cinctae, 
cellulas macrosphaeroideas non gerentes. — Apothecia sessilia, congesta, 
ellipsoideo-oblonga, recta vel curvata, simplicia, 0,3—1 mm longa, nigra, 
opaca; discus rimiformis, tenuis, lobiis discum superantibus: excipulum 
crassiusculum, carbonaceum, integrum, labiis integris, inflexis; hymenium 
in sectione transversali plus minus cordatum, purum, I e coeruleo vire- 
scenti-obscuratum (ascis subviolaceis); paraphyses densae, leviter inaequales, 
ramosae et subintricatae, eseptatae, ad 1,5 u crassae; asci ovales vel ovali- 
oblongi, 8 spori; sporae bene evolutae rarae, primum decolores, demum 
fuscescentes, ellipsoideae vel subovales, utrinque rotundatae, triseptatae, 
septis angustis, 12—16 u longae et 7,5—8,5 u latae. — Conceptacula pycno= 
conidiorum immersa, oblonga vel subpyriformia, vertice nigro, opaco; peri- 
fulerium coerulescenti-nigrum, inferne angustius, NO, aeruginascens; fulcra 
exobasidialia; basidia fasciculata, pycnoconidiis breviora; pycnoconidia fili- 
formia, varie curvata vel hamata, utrinque retusa, 16—20 u longa et ad 
1 u lata. 
