[Vol. 2 

 350 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



example (Brooks, '10), or a boring organ, a terebrator 

 (Lindau, '99). Zukal ('89) interpreted the trichogyne of 

 Pyronema confluens as a haustorium to provide food for the 

 large ascogonium with its numerous ascogenous threads. 



Recent investigations on Collema pulposum (Bachmann, 

 F. M., '13) have revealed an interesting departure in the rela- 

 tion of the trichogyne and spermatia from that thus far found 

 in other lichens, and is in strong contrast with the condition 

 found by Stahl in Collema. The ''spermatia" are not free 

 and are not formed in large numbers in superficial receptacles, 

 but are imbedded in the thallus and remain attached to the 

 supporting hypha. The trichogyne does not extend to the 

 surface but migrates through the interior of the thallus, seeks 

 the spermatia and fuses with one. Then the trichogyne un- 

 dergoes the usual deterioration, but no evidence was obtained 

 of the migration of the nucleus of a spermatium to the as- 

 cogonium, although a nucleus supposed to be the sperm 

 nucleus appears to have been observed in the terminal cell of 

 the trichogyne. 



In the red algae the only variations and progression in the 

 trichogyne is in variations in length to meet the requirements 

 of thin or thick cortex, some more or less sinuous or spirally 

 wound, and a few stout and blunt. It is universally a con- 

 tinuous, enucleate,^ prolongation of the oogone, i. e., not sep- 

 tate nor a separate cell. So far as we know the sperm always 

 functions in the red algae. In the sac fungi, there is great 

 variation and marked morphological progression from an 

 oogone without a trichogyne through short one-septate 

 trichogynes to long, simple, several-celled ones, and also to 

 profusely branched, multi-septate trichogynes. It is more 

 comprehensible to regard this progression and variation in the 

 light of evolution from the simple to the complex, in the as- 

 comycete phylum, independent of the red algae, than to con- 



^ Davis ( '96 ) describes the trichogyne of Batrachospermum as having a 

 nucleus of its own, but it is not separated from the egg nucleus by a wall until 

 just prior to the development of the gonimoblasts from the egg. He also states 

 that the sperm nucleus never passes out of the trichogyne into the egg. How- 

 ever, Schmidle ( '99 ) and Osterhout ( '00 ) find no trichogyne nucleus and describe 

 a real fertilization by fusion of sperm and egg nucleus. 



