CUTLERIALES (ISOGENERATAE) 155 



therefore, Cutleria must be regarded as a modified member of the 

 Isogeneratae or else it must be separated from Zanardinia and put 

 in a separate family in the Heterogeneratae. 



CuTLERiACEAE : Cutleria (after Miss Cutler). Fig. 107. 



The gametophyte and sporophyte generations are distinctly 

 heteromorphic and also differ in their seasonal occurrence, the 

 former being a summer annual whilst the latter is a perennial 

 reaching its maximum vegetative phase in October and November 



Fig. 107. Cutleria multifida. A, plant ( x i). B, young seedling. C, seedling 

 slightly older to show branching. D, transverse section of thallus with unilocular 

 sporangia. E, female gametangia. F, male gametangia. G, ''Aglaozonia" stage. 

 (A, original; B-D, G, after Oltmanns; E, F, after Yamanouchi.) 



with a peak fruiting period in March and April. The gametophyte is 

 an erect flattened thallus rendered fan-like because of the repeated 

 dichotomies. The thallus and apices are clothed with tufts of hairs, 

 each with a basal growing region, whilst the oogonia and antheridia, 

 which are borne on separate plants, occur in sori on both sides of 

 the thallus. The antheridia, with which hairs are sometimes 

 associated, are formed in clusters from superficial cells of the 

 thallus that divide to produce a stalk cell and an antheridium 

 initial. The mature antheridium contains about 200 antherozoids, 

 each of which possesses two chromatophores, and they are much 



