XI 



LEPTOSPORANGIATJE HETEROSPOREJE 



413 



Fig. 240. — Azolla Uliculoides. A, Vertical longitudinal section of the stem apex, X600; 

 r, mother cell of a root; B, three successive transverse sections just back of the 

 apex; tn, the median wall; L, mother cell of a leaf, X600; C, single lobe of a 

 young sterile leaf, X600; D, fertile leaf segments with two very young sporocarp 

 rudiments, X6oc; E, longitudinal section of young macrosporangium, showing the 

 young indusium {id), X600; t, first tapetal cell; F, older macrosporangium com- 

 pletely surrounded by the indusium, X350; n, Anabcena filaments. 



