276 PHYLOGENY 



the fungus genus Verrucula. It was established by Steiner 1 to include two 

 species, V. cahirensis and V. aegyptica, their perithecia being exactly similar 

 to those of Verrucaria? in which genus they were originally placed. Both 

 are parasitic on species of Cahplaca (Placodium). The former, on C. gilvella, 

 transforms the host thallus to the appearance of a minutely lobed Placodium ; 

 the latter occupies an island-like area in the centre of the thallus of Calopiaca 

 interveniens, and gives it, with its accompanying parasite, the character of 

 an Endopyrenium (Dermatocarpon), while the rest of the thallus is normal 

 and fertile. 



Zahlbruckner may have argued rightly, but it is also possible to regard 

 these rare desert species as reversions from an originally symbiotic to a purely 

 parasitic condition. Reinke came to the conclusion that if a parasitic 

 species were derived directly from a lichen type, then it must still rank as 

 a lichen, a View that has a direct bearing on the question. The parallel 

 family of Pyrenulaceae which have Trentepohlia gonidia is considered by 

 Zahlbruckner to have originated from the fungus genus Didymella. 



Compound or stromatoid fructifications occur once and again in lichen 

 families; but, according to Wainio 3 , there is no true stroma formation, only 

 a pseudostroma resulting from adhesions and agglomerations of the thalline 

 envelopes or from cohesions of the margins of developing fruit bodies. 

 These pseudostromata are present in the genera Chiodecton and Glypkis 

 (Graphidineae) and in Trypetheliuw, Mycoporium, etc. (Pyrenocarpineae). 

 This view of the nature of the compound fruits is strengthened, as Wainio 

 points out, by the presence in certain species of single apothecia or perithecia 

 on the same specimen as the stromatoid fruits. 



b. CONIOCARPINEAE. This subseries is entirely isolated. Its peculiarity 

 lies in the character of the mature fruit in which the spores, owing to the 

 early breaking down of the asci, lie as a loose mass in the hymenium, while 

 dispersal is delayed for an indefinite time. This type of fruit, termed a 

 mazaedium by Acharius, is in the form of a stalked or sessile roundish head 

 the capitulum closed at first and only half-open at maturity rarely, as in 

 Cyphelium, an exposed disc. There is a suggestion, but only a suggestion, of a 

 similar fructification in the tropical fungus Camillea in which there is some- 

 times a stalk with one or more perithecia at the tip, and in some species early 

 disintegration of the asci, leaving spore masses 4 . But neither in fungi nor in 

 other lichens is there any obvious connection with Coniocarpineae. In some 

 of the genera the fungus alone forms the stalk and the wall of the capitulum ; 

 in others the thallus shares in the fruit-formation growing around it as an 

 amphithecium. 



The semi-closed fruits point to their affinity with Pyrenolichens, though 



1 Steiner 1896. - Muller-Argau 1880. 8 Wainio 1890, p. xxiii. * Lloyd 1917. 



