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DR JOHN M‘LEAN THOMPSON ON 
irregular scales, typical examples of which are^shown in text-fig. 19. These closely 
invest the short massive stalks of the sporangia, and clothe the steep margins of 
the elevated receptacle (fig. 66). The position and vascular supply of the sorus, 
and the variation in arrangement and number of sporangia, are features typical 
of Gleichenia, and the possession of them greatly strengthens the Grleicheniaceous 
affinity of Stromatopteris. 
Seven sporangia were available for study. They were borne on separate sori, and 
it was impossible to judge by them as to what credence is due to Mettenius’s remark 
that in the sporangia of Stromatopteris dehiscence is extrorse. Bxtrorse dehiscence, 
as a defined character, is unknown in the Gleicheniacege, although -variations in 
sporangial orientation occur, but it may be said that in at least two of the 
sporangia available dehiscence appeared to be introrse. The sporangia varied in form 
and size, and the degree of variation in these respects may be judged by the 
illustrations given (figs. 62, 63, 64, 65, and 71-74). These sporangia have all been 
drawn to the same scale, and are represented in various positions. The sporangial 
stalks are short and massive (fig. 66) and the heads are more or less globular. The 
largest sporangium found is depicted in figs. 62 and 63. From these views it will 
be seen that the annulus is transverse, irregular, and massive. The region of 
dehiscence is well defined, and dehiscence is vertical. This sporangium was open, 
and accordingly its spore output could not be estimated. The sporangium re- 
presented in figs. 67 and 68 is of the same general form as the one just described, 
but its annulus is oblique and uniseriate. The zone of dehiscence is ill defined 
and narrow, but dehiscenoe is clearly vertical. There is here seen the kettle-drum- 
shaped sporangium typical of Gleichenia. This sporangium had been entirely 
emptied of its spores. A much smaller sporangium, but similar in form to the 
one just described, though possessed of a wider region of dehiscence, is shown in 
figs. 64 and 65. It merely illustrates that variation in sporangial size common in 
Gleichenia itself, and which may be due to faulty nutrition and arrest. One 
large sporangium of the type just described was found to be unopened. Its spores 
