400 INTRODUCTION TO CRYPTOGAMIC BOTANY. 



beneath them. Their nucleus is compound and bears elliptic 

 spermatia. In Lichina pygmcea, the spermatogonia are 

 seated on the perithecia. Their nucleus is simple ; in both the 

 spores are more or less united into moniliform series. The 

 species are widely dispersed, but luxuriate in the tropics. Paulia 

 is a genus of the southern hemisphere, as is also Mastodia, 

 but of far colder localities. Ephebe is, I believe, confined to 

 the northern hemisphere. Lichina occurs in New Zealand. 



II. Gymnocarpei, Schrad. 



Hymenium or thalamium at length exposed, disciform, with 

 or without a distinct excipulum ; tips of paraphyses often 

 charred by exposure. 



436. We have considered, first, those Lichens in which the 

 fructification is formed more or less after the fashion of Sphce- 

 ria; whether exposed or scattered within the thallus, or included 

 in certain swollen and privileged portions of it. We have 

 now to proceed to those in which the disc is essentially open, 

 and not merely exposed by a rupture of the cellular tissues of 

 the Lichen. Something like such an expansion was noticed 

 under Siphida ; but it is very far from the structure of the 

 group now to be described. This order includes the great mass 

 of Lichens, in every possible variety of form and habit ; the 

 essential chararacters, however, still remain the same, and the 

 group so natural that they run into each other, so as to leave 

 no very striking distinctions. 



1. Caliciei, Fr. 



Thallus horizontal ; hymenium at first closed by a veil, then 

 exposed, contained in a pedicelliform or sessile excipulum. 



437. We have here a group differing singularly in habit 

 from the rest. The crust is ill-developed in general, but the 

 striking characters consist in the distinctly stipitate or more 

 rarely sessile excipula, looking like little flat-headed pins stuck 

 into the crust, the hymenium of which is covered by a delicate 

 veil, which at length vanishes, and exposes the pulverulent 

 mass of spores, making an approach, as regards technical cha- 

 racters, to SphcBropJioron. The peduncle is very much of the 

 same substance as the immediate supporter of the hymenium ; 

 and totally different from the crust, though proceeding from 



