LYCOPODIALES 



first year's growth. From the description of Thomas it thus appears that 

 the embryology is just what would be expected of a plant which had 

 already been recognised as repeating in its annual cycle a development 

 similar to that of L. cernuum. 



The yearly growth of Phylloglossum resembles in many features that 

 of the embryo : it originates at the apex of the storage-tuber formed 

 during the preceding year, and its pnnctiim vegetationis retains its identity 

 as the centre of the new growth. Sometimes only a single leaf is formed, 



B 





. 





FH.. 1 88. 



A and />' embryos of Lycopoditmi cernuiini, .showing pmtoi.orni. 

 = foot; cot cotyledon ; J ', /'-', etc. = successive leaves; r = root; 

 X35. (After Treub.) 



.-/---/< tui 



but usually several more in strong plants : they arise in succession laterally 

 around the apex, but are definite neither in number nor in position. In 

 those cases where the plant does not form a strobilus, the apex, which 

 lies centrally among the leaves, becomes depressed, while the tissue 

 surrounding it, continuing to grow actively but unequally, a process is 

 formed which develops into the new tuber (Fig. 189 A, i;). \Vhere a 

 strobilus is formed it arises directly from the apex (Fig. 189 c, D, E), and 

 a new provision has to be made for the formation of the new tuber. 

 This appears adventitiously at the base of ,the peduncle, as a depression 

 which is carried outwards on an elongating process due to active and 



