INTRODUCTION TO CRYPTOGAMIC BOTANY. 



407 



tinct epidermal cellular coat. Collema is thus closely con- 

 nected with Leptogium, which is further distinguished by its 

 marginate disc. The gonidia differ very much from those of 

 other Lichens. In Collema and its closer allies, they are 

 minute and arranged in moniliform rows ; but in Synalyssa 

 they resemble those of Paulia (Fig. 84, a), arising from the 

 fissiparous division of each gonidium, accompanied by a bifur- 

 cation of the supporting thread ; while in Omphalaria (Fig. 

 86, e, f) their generation resembles that of Hwmatococcus. 

 The fact was first noticed, I believe, by Montague, imder 



,1) /" 



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i i 



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Fig. 86. 



a. Stylospores of AhrothaUus Smithii, Tul. From specimens gathered 

 at Craigie Hill by Dr. Lindsay. 



h. Synalyssa vulgaris. From specimens gathered at Bristol by Mr. 

 Thwaites. A portion of the plant with its fastigiate fruit and palmel- 

 loid, gonidia one of which is represented more highly magnified in the 

 act of division. 



c. Asci, sporidia, and paraphyses of the same. 



d. Hsematococcoid excrescences which roughen the thallus. These 

 are tinged with red. 



e. Hsematococcoid gonidia of Omphalaria nummularia, Mont. From 

 an Algerian specimen given to me by Dr. Montague. The upper cell 

 is darker than the rest, being near the surface. 



/. Filaments of medullary tissue, forming meshes as in Omphalaria 

 Oirardi, two cells of the cuticle, and ascus with sporidia and para- 

 physes. 



All more or less magnified. 



