FAMILIES AND GENERA 313 



"pycnidia" are still imperfectly known. In designating the gonidial algae, 

 the more comprehensive Protococcaceae has been substituted ior Protococcus, 

 as in many cases the alga is probably not Protococcus as now understood, 

 but some other genus of the family^. 



Subclass I. ASCOLICHENS 



Series I. PYRENOCARPINEAE 



It is on mycological grounds that Pyrenocarpineae are placed at the 

 base of lichen classification. There is no evidence that the series was first 

 in time. 



I. MORIOLACEAE 



This family was described by Norman^ in 1872 from specimens col- 

 lected by himself in Norway or in the Tyrol, on soil or more frequently on 

 trees. There seems to have been no further record, and Zahlbruckner, 

 while accepting the family, suggests that an examination or revision may 

 be necessary. 



The thallus is crustaceous. The algal cells, Protococcaceae, occur either 

 in groups (sometimes stalked) surrounded by a plectenchymatous wall and 

 called by Norman "goniocysts," or they form nests in the thallus termed 

 "nuclei" which are surrounded by a double wall of plectenchyma, colourless 

 in the interior and brown outside. Norman invented the term "Allelositis- 

 mus," which maybe rendered "mutualism," to indicate, this peculiar form 

 of thallus. The species of Spheconisca are fairly numerous on poplars, willows 

 and conifers : 



Algae in •'goniocysts" I. *Moriola Norm.' 



Algae in double-walled "nuclei" ... 2. *Spheconisca Norm. 



II. Epigloeaceae 



The family consists of but one genus and one species, Epigloea bactrospora, 

 and, according to Zahlbruckner, further examination is necessary to make 

 certain as to the lichenoid nature of the plant. 



Zukal'' found the perithecia scattered over the leaves of mosses, and he 

 alleges that hyphae connected with the perithecium were closely associated 

 with the alga, Palmella botryoides, and were causing it no harm. Along with 

 the perithecia he also found minute pycnidia. The "thallus" is of a gelatinous 

 nature and homoiomerous in structure; the perithecia are soft and clear- 

 coloured with many-spored asci and colourless one-septate spores. 



The small globose pycnidia contain simple sporophores and acrogenous 

 straight or slightly bent rod-like spores. 



Asci many-spored ; spores one-septate, i. *Epigloea Zukal. 



^ See p. 56. ^ Norman 1872 and '74. 



' Genera marked with an asterisk have not been found in the British Isles. * Zukal 1890. 



