THE TUBERS OF ANTHOCEROS TUBEROSUS. 53 



dry and dies there will still remain several living cellular masses, filled 

 with food materials, which will be enclosed and protected by the remains 

 of the dead thallus. These would probably be able to survive a con- 

 siderable time and then give rise to new plants under circumstances 

 favourable to their germination. It is possible that this plant forms 

 the cellular masses in the thallus before it produces the stalked tubers, 

 and, thus, early secures protection against extinction by drying during 

 hot periods. That this is a possible explanation is supported by the 

 fact that, in the dry herbarium specimens at my disposal, the histology 

 of the cells of these internal food-laden cells is quite good, and the 

 normal shape of the cells is retained, whereas the ordinary cells of the 

 thallus are shrunk and collapsed. 



The specimens used in this investigation were obtained from the 

 Carrington Herbarium in the Manchester Museum, Owens College, and 

 the work was carried on in the Botanical Laboratory of the College 

 during the Lent Term of this year, under the direction of Professor 

 Weiss, to whom I am indebted for advice and criticism. 



EXPLANATION OF FIGURES IN PLATE III. 



Fig. 1. — Longitudinal section of a tuber (with its stalk) of Anthoceros 

 tuberosus, x 100. 



Fig. 2. — Three cells from the internal portion of the tuber, x 1,000. In 

 the two upper cells the proteid granules are shown, and in the lower one the 

 oil drops. 



C. Cork cells. 



G. Proteid Granules. 



H. Hairs. 



N. Nucleus. 

 O. Oil-drops. 

 P. Protoplasm. 



