LICHENES. 



303 



has "succeeded many times" in finding gonidia so connected 

 to the hyphae by more than one branch. 



400. With regard to the origin of gonidia, Fries asserts 

 that the hypha-branches swell up at their ends, become glob- 

 ular, and, after a while, filled with green contents.* He, 

 however, does not speak of any observations of his own upon 

 Avhich he bases his statement. Berkeley! likewise regards 

 them as developed from the mycelium, but made no observa- 

 tions which can be considered conclusive. Speerschneider's 

 observations, \ in 1853 to 1857, along with those of Bayr- 



Fig. 210. Mallotixm (or Leptogium) Ifi/tleiibrandii. a, vertical section through the 

 thallnn, w, the under side, x 190 ; 6, portion of a very thin section near the under 

 side, showing three gonidia chains, two hyphfe, a portion of the lower limitary tissue, 

 and two large and several small hairs, which are organs of attachment, x 390. After 

 De Bary. 



hoffer, some years earlier, appear to be, in reality, the ones 

 upon which the view that gonidia develop from the hyphae 

 depends ; their statements appear to have been accepted and 

 repeated by lichenologists without sufficient inquiry. The 

 other errors of observation and interpretation made by these 

 observers render their testimony upon the question of the 

 origin of the gonidia of doubtful value. Schwendener, in 



* " Lichenograpliia Scandinavica," 1871. 



f " Introduction to Cryptogamic Botany," 1857. 



t In Botanische Zeitung, 1853, 1854, 1855, 1857. 



" Einiges uber die Lichenen und deren Befruchtung," 1851. 



