1894] NEW-YORK ISIICROSCOPICAL SOCIETY. 67 



the hyphse, forming an irregularity or projection upon the sur- 

 face, or a branch of the thallus may start from such a point. In 

 isome sections there appeared connected with this feature small 

 bundles of gonidia and hyphae not unlike soredes. These may 

 have been simply the beginnings of further growth. A somevvhat 

 similar growth appears on the sporophore referred to below. The 

 peculiar configuration of the thallus that characterizes both the 

 margin and surface of the mature lichen seems to be largely due to 

 the behavior of the mycelium in blocking the growth of the goni- 

 dia with mats of filaments. This interposition of dense felts at 

 various places on the margins results in a very irregular, almost 

 ragged, outline of the thallus. I could not always satisfy myself 

 that the lobing, particularly in the young thallus, was brought 

 about in this manner ; but its frequent observation leaves little 

 room for doubt that the cause of the peculiar form of growth is 

 as above stated. 



The sporocarp appears to arise from a lifting up of the thallus, 

 which, growing into a tubular mass, forms the receptaculum. 

 Though diligent search was made for the archicarp in all these 

 early stages of growth, not the slightest evidence of it could be 

 found. Nor did any section show any trace of or give indication 

 of sexuality. 'I he hypothecium and paraphyses could be recog- 

 nized at an early age, especially the latter, which appeared about 

 as soon as there was any outward evidence of the sporocarp. 

 The asci appeared much later, and in fact could not be recog- 

 nized till the hymenium was developed and began to show its 

 characteristic color. In this state the ascogenous hyphse could 

 not be traced into the subhymenial layer, and, in truth, had the 

 same appearance as the filaments generating the paraphyses. 

 The growth of the asci extended over a considerable period, 

 new sacs appearing beside those apparently empty. The apo- 

 thecia are spherical, surmounting the stipe like a cape, and of a 

 brown color from the closely packed filaments of the hymenium. 

 The receptaculum shows a marked variance in its structure from 

 that of the thallus. As mentioned above, it is cylindrical, of 

 especially dense tissue, the hollow central portion being traversed 

 by irregular strands from the periphery. But, unlike the thallus, 

 the gonidial layer is largely developed upon the outside. As 

 soon as the filaments of the medulla begin to lift up to form the 



