5° 



BOTANICAL GAZETTE [January 



often occupying almost all of the thallus. The cavities have no 

 regular chlorophyllose filaments, although single cells frequently 

 project into them (figs, n and 16). In these respects Aytonia 

 differs markedly from Marchantia, Fegatella, and Targionia. 



The close tissue of the thallus is generally infested with intra- 

 cellular fungi (fig. 6), filamentous, non-septate, not contracted in 

 passing through the walls, branching irregularly, and forming 

 sporelike bodies occasionally as vesicles within a swollen part of 

 the main filament or in short branches. One naturally questions the 

 origin of the fungi and the relation existing between them and the 

 liverworts. Cavers (6) reports fungi in many liverworts, and says 

 they are nearly always related to the soil, always occurring with 

 humus; then he finds them traversing the rhizoids and extending 

 into the lowest layers of the compact tissue; he thinks the fungus- 

 bearing plants are larger and thicker than others. Golenkin (12) 

 reports "endotropic mycorhiza" in five liverworts, and thinks they 

 are "for storing water." Nemec (15) implies the entrance of the 

 fungi through the rhizoids, and describes a pseudoparenchyma 

 formed by them on the wall of the cells of the thallus. Garjeanne 

 (10) also finds them entering through the rhizoids and thinks the 

 relation may be accidental, a case of true parasitism, or a case of 

 true symbiosis. Miss Clapp (7) is the only one who has traced 

 the history of the infection back to the very early stages of the 

 sporeling. She finds fungi in as young a plant as the 4-celled stage, 

 and states that development is hastened by the presence of the 

 fungus. According to her, infection of rhizoids occurs from the 

 thallus. I am inclined to think that both methods of infection of 

 the rhizoids may happen; that the plant may become infected at 

 any stage of development; when considerable mycelium has 

 developed, the hyphae may grow out through the rhizoids; and 

 when the infection occurs late the hyphae may enter through the 

 rhizoids. In my material the fungi are only in the older parts of 

 the thallus, and when they occur in rhizoids seem to be always 

 growing toward the thallus (fig. 7) ; but in living material of Mar- 

 chantia and Fegatella I have found the hyphae passing out through 

 the rhizoids. I find no "pseudoparenchyma" or balling up of 

 hyphae, described by Nemec. 



