SPECIAL MORPHOLOGY: LICHENES. 159 



single, broader, elliptical, tender-walled cells (sporangia, thecce, 

 asci, Auct.), grow up between them, and soon become filled with 

 a viscid matter. Within these, cell- nuclei are developed, and from 

 them cells which form simple spores ; or, again, two or more cell- 

 nuclei appear, from which cells, and then double-spores, are deve- 

 loped. During this process, the whole sporocarp approaches by 

 degrees nearer to the surface of the plant, being always covered 

 by a substance the tissue of which it is difficult to determine, but 

 which appears to be partly the product of the paraphyses, fre- 

 quently occurring as a black, finely granular, mass, as is especially 

 the case in Pyrenomycetes and Pyrenothalami ; and partly, in the 

 subsequently expanded fruits, composed of a thin lamella of the 

 cortical layer of the thallus, and is sooner or later destroyed. 

 Remaining in this closed condition as a nucleus, it forms the fruit 

 of Pyrenomycetes and Pyrenothalami (sporangia angiospora nu- 

 cleo pradita, Meyer). In others it bursts through the upper 

 surface, spreads itself more or less into a linear cup, or disc- shaped 

 (apotheciuni) patella, when circular ; lirella, when linear ; (sporo- 

 carpia angiospora laminam gerentia, Meyer). It sometimes raises 

 a part of the upper surface of the plant, which then appears as 

 a margin (margo thallodes, excipulum thallodes) ; at others, again, 

 this portion grows more decidedly out, and raises the sporocarp 

 upon a pedicle (podetiurri) varying in height. In most Lichens the 

 sporangia remain long closed ; in some, however, they open early, 

 and the spores then lie free upon the sporocarp (sporocarpia gym- 

 nospora, Meyer ; coniothalami). 



The history of the development of the fruit of the Lichens is still 

 very incomplete. Meyer has furnished us with much valuable informa- 

 tion concerning all that may be seen by the naked eye, or an ordinary 

 lens ; as, for instance, his valuable account of the development of the cup- 

 shaped fruits of the species of the Cladonia, appearing either on the 

 margin in new fruits, or expanding into cups. I have sketched the 

 process from my own observations on Borrera ciliaris, Lecidea san- 

 guinea, Sphcerophoron coralloides, Calycium trachelinum, Parmelia 

 subfusca, &c. By way of illustration I will here give the development of 

 the sporocarp of Borrera ciliaris (figs. 126. 127.), and at Plate II. fig. 9. 



a j27 



fe^N 

 126 



86 Borrera ciliaris ; a portion of the plant. a, First beginning of a sporocarp 

 6, The same more fully developed, c, Quite developed. 



87 Section through the sporocarp of the Borrera ciliaris, in three different conditions 



