1912] CLAPP—ANEURA PINGUIS 189 



lacking, which must depend upon the conditions of light and 



moisture 



with the development of the 

 t in it when present. Where 



spore is that the fungus plays some part in it when present, 

 the spores fell from the capsule and germinated on the cotton, and 

 in another case where the capsule did not open wide but spores in 

 the line of the valves germinated, a fungus was found infecting the 

 plants. These sporelings were all past the two-celled stage (figs. 



mu 



rhizoids. In 



ment 



o 



many- 



leafy and some thalloid liverworts (Nemec 20, Bolleter 2, 

 Gar jeanne 8, Cavers 5), but only in one case does Garjeanne 



with the 



in anv cell of the sDorelinz (figs. 64-66) and 



the 



hyph 



are found in the cells. At first the cells are not killed, fungus, 

 plastids, and nucleus all being present. Gradually the plastids 

 disappear but the nucleus remains longer. In cells adjoining and 

 near to the infected ones, starch of the plastids has been transformed 

 into dextrine. 



A majority of the plants of the field are infected irrespective of 

 habitat. One would like to know whether spores are also infected 

 early or whether the laboratory conditions were such as to favor 

 infection. It is hardly probable that any such relation exists 

 between spores and fungus as Bruchmann has found for species of 

 Lycopodium. It is more likely, as Garjeanne thinks, a chance 

 condition, and not at all an endophytic fungus of mycorrhiza plants. 

 Thalli from the field usually have the fungus a short distance 

 behind the actively growing region, and sometimes extending along 

 two-thirds of the dorsal surface. Is it possible that this is one of 

 the main causes for the dying back of the thallus i 



Rhizoids are commonly filled with strands of the hyphae (fig. 

 68). Infection of the rhizoids commonly occurs from the thallus, 

 and when chloroplasts are still present. The elaborate pseudo- 

 parenchyma of fungi described by Nemec (20) at the base of the 

 rhizoids is lacking, but there are knots of hyphae. Rarely, also, 



? 



