266 PYRENOCAKPEI [OBRYZCM 



opening above by a pore ; spores 8 in the ascus, fusiform, simple 

 or septate, colourless. 



Described at first as homogeneous with the thallus on which it 

 grows (CoUemacese) ; its parasitic nature was determined by 

 Nylander (I. c). 



1. 0. corniculatum WaUr. 1. c. ; Xyl. in Flora Iviii. p. 106 

 (1875). — Thallus none proper. Perithecia immersed or almost 

 superficial on the laciniae of the host thallus, globose ; perithecial 

 wall entire, thin, brownish ; paraphyses none ; asci small, 

 somewhat elongate, swollen in the middle ; spores shortly 

 fusiform, simple, with several guttulae and pointed at each end, 

 0,016-21 mm. long, 0,005-6 mm. thick ; hymenial gelatine not 

 tinged with iodine. — Verrucaria corniculata Leight. Lich. Fl. 

 ed. 3, p. 497 (1879). 



Bab. Parasitic on various species of Leptogium. — Disir. Eai-e in 

 S.W. England. — B. M. Weston-super-Mare, Somerset ; Cowcombe 

 Wood, Chalford and near Cirencester, Gloucestershire. 



2. 0. dolichoteron Nyl. in Flora Ui. p. 353 (1872).— Thallus 

 none proper. Perithecia projecting like small golden balls 

 from the tissue of the host, scattered, numerous, globose ; 

 perithecial wall entire, brownish ; paraphyses none ; spores 

 narrow, fusiform, colourless, 3-5-septate, 0,023-27 mm. long, 

 0,004-5 mm. thick. — Verrucaria dolichotera Leight. Lich. Fl. 

 ed. 3, p. 497 (1879). 



Differing from the preceding in the lighter coloured perithecia, and 

 in the character of the spores. 



Hcib. Parasitic on CoUemacese. — B. M. Craig Tulloch, Blair 

 Athole, Perthshire (on Collema melcenum). 



DERMATOCAEPACE^. 



Thallus spreading, foliaceous or squamulose or subcrustaceous, 

 corticated on one or both surfaces- or non-corticated, under 

 surface naked or with rhizin». Perithecia simple, more or less 

 immersed in the thallus, opening by a pore at the apex. 

 Spermogones with short straight spermatia. 



Three genera of the Order occur in the British Isles, well differen- 

 tiated by the form of thallus or spores. Endocarpon is further 

 distinguished by the presence of green algal cells (gonidia) in the 

 hymenium as weU as in the thallus ; they are produced in loose 

 filaments or masses alongside of the asci and paraphyses, and are 

 ejected from the peiithecimn with the mature spores. 



Gonidia not present in hymenium. 



Spores simple 101. Dermatocarpon. 



Spores septate 102. ITormandina. 



Spores muriform 103. Dacampia. 



Gonidia present in hymenium. 



Spores muriform 104. Endocarpon. 



