Fig. 1 1. LeafabnormalitiesinstarvedandmutiIatedyoungplantsofOj7n«««/are|^a//^L., after Lang (1924). 

 a. Part of an uninjured but starved specimen showing a bud {h) on one of the petioles, x 6. 

 h. The bud of a more highly magnified, x 20. c. One leaf from a similar plant showing more 

 extreme modification; there is no lamina, but instead the petiole forks and one fork bears a pro- 

 thallus [p) at its tip and a bud laterally, x 7. d. Whole plant found detached and without roots 

 in a crowded pan. x 6. Of the two expanded leaves one is normal and the other bears five 

 prothalli at the tips of the veins. This leaf, after being detached and laid on soil, was the start of the 

 polyploid series in Osmunda. For other examples of apospory of this type see the photographs in 

 Figs. 8a and 12. 



27 



