258 



POPULAR HISTORY OF LICHENS. 



it has been supposed that they attain maturity externally to 

 the theca, or are what have been denominated " naked 

 spores." It is probable however that this phenomenon is 

 more apparent than real. The thecse are narrow, linear, and 

 very delicate. In progress of the growth of the spores they 

 frequently become so closely incorporated with their contents 

 as to be inseparable and indistinguishable therefrom ; in rare 

 cases however they are found containing a linear series of 

 mature spores. The spores of the Calicia are among the 

 smallest of Lichen-spores; they are either simple or bilo- 

 cular and usually dark-coloured. Several species of this 

 family, from their great resemblance, were once classed under 

 the genera Mucor and Trichia of the Fungi. 



Apothecia (tlialamium) black. 

 t Apothecia sessile or substipitate. 



1. Calicium turbinatum (turben, the toy called a top). 

 Apothecium concave or flat ; base stipitiform ; exciple pyri- 

 form or turbinate, externally shining ; margin thick, inflexed, 

 paler. Spores small, spherical, simple. (E. B. 2520.) 



Always parasitic on Pertusaria communis, and common in 

 some lowland woods. Its spermogones are to be looked for 

 with the lens, on the thallus of P. communis, in the form of 

 small black spots scattered among the apothecia. They are 



