ORDER LECANORALES (tHE DISK LICHENS) 



221 



Fig. 73. Lecanorales, Family Collemaceae. (A, B) Collema crispum Ach. (A) Asco- 

 gonium and trichogyne. (B) Apical cell of trichogyne, showing sticky surface. (C) 

 CoUemodes hachmannianum Fink. Ascogonium and trichogyne growing to clusters of 

 sperm cells produced within the thallus. (D-G) Collema pulposum (Bernh.) Ach. 

 (D) Habit sketch. (E) Cluster of apothecia. (F) Section through apothecium. (G) 

 Ascus. (A-B, after Baur: Ber. dent, botan. Ges., 16(10): 363-367. C, after Bachmann: 

 Ann. Botany, 26(103) :747-760. D-G, after Schneider: A Text-book of General 

 Lichenology, Binghamton, N.Y., Willard N. Clute & Co.) 



