THE PSILOTALES 



available refers to tetraploid Psilotum which has now been obtained from New Zealand, 

 Australia, Malay, and perhaps Japan, while a corresponding diploid has only so far been 

 found in Ceylon, though it may easily be present in other parts of the world. A char- 





I 



w. 



ir^ 





Tmesipferis 2n =■ over 400 



Fig. 240. Explanatory diagram to Fig. 239a. x looo. 



acteristic aberration of the spindle reported from Japan, New Zealand and Australia has 

 been shown by Professor Barber of Tasmania to be of metabolic origin in unfavourable 

 environmental conditions. The causes of the presence of anomalous vascular tissue in 

 the diploid gametophytes described by the late Dr Holloway from New Zealand are still 

 uncertain, and a genuine haploid prothallus is still undiscovered in this genus. Further 

 study of both genera and of all species in them is much to be desired. 



243 



16- 



