Manchester Memoirs, Vol. xli. (1896), No.%. 5 



them.* The oil found in these tubers closely resembles that 

 which Pfeffer found in other Liverworts in its solubility 

 in various reagents, its fluid condition at a temperature 

 of I2°C, the difficulty experienced in its saponification 

 with potash, and in the fact that the oil is not vaporised 

 on heating to I40°C. 



Besides these stalked tubers projecting ventrally into 

 the soil, there are analogous bodies formed in the sub- 

 stance of the thallus, which have not hitherto been 

 described. These are produced by the formation of a 

 cellular mass (like that of the inner part of a stalked 

 tuber) between the upper and lower layers of the thallus. 

 The cells of these tuberous masses have the same structure 

 and contents as those in the inner portion of the external 

 tubers. These cellular masses are usually oval in shape, 

 and their average length and breadth are '2 mm. and 

 •15 mm. respectively. They are somewhat flattened dorso- 

 ventrally, their thickness being *i — '15 mm. In several 

 sections, I have found one of these internal masses at 

 the base of the stalk of an ordinary (but small) tuber. 

 This suggests that, possibly, the stalked tuber in question 

 was in process of formation, and that the cells at the 

 base of the stalk were storing up food materials, which 

 would subsequently be passed into the tuber. Internal 

 masses of considerable size occur in other places in the 

 thallus where there is no sign of the formation of a 

 stalked tuber, and these probably always remain in the 

 thallus, and are independent of any external tuber. 



Regarding the function of the tubers, the Synopsis 

 says they should be looked upon as gemmae, and Ruge 

 (Flora, 1893, p. 306) suggests that this process of 

 vegetative reproduction is an adaptation to a mode of life 

 in which the plants are subjected to periodic droughts. 

 In support of this view he mentions the fact that the four 



* Pfeffer. Die Oelkorper der Lebermoose. Flora. Jan., 1874. 



