xxvj 



STAUROPTERIS 



467 



Scott^ and figured by Bertrand^, doubtless represents the 

 much reduced lamina of the highly compound leaves ; it may 

 be compared with the green outer cortex of Psilotum shoots 

 and with the lacunar tissue in the capsule of the common 

 moss, Funaria hygrometrica. 



The rachis reproduced in fig. 321 is surrounded by an 

 enormous number of sections, some transverse, others more or 

 less vertical, of branchlets of various sizes. Fig. 310, B, shows 

 the three-rayed vascular axis of a branch of a lower order than 



a- 



Fia. 321. Stauropteris oldhamia: a, sections of pinnae. (xlO. Prom a 

 section in the Cambridge Botany School Coll.) 



those seen in fig. C, and the single vascular strands of still finer 

 ramifications of the leaf The extraordinary abundance of axes 

 of different sizes, many of which are cut in the plane of 

 branching, in close association with the rachises of Stauropteris 

 affords a striking demonstration of the extent to which the sub- 

 division of the firond was carried in a small space. The leaves 

 must have presented the appearance of a feathery plexus of 

 delicate green branchlets devoid of a lamina, some of which 

 bore terminal sporangia. It may be that the delicate fronds 

 were borne on a slender rhizome which lived epiphytically in a 

 moist atmosphere on the stouter stems of a supporting plant. 



' Scott (05») p. 11-5. ' Bertrand, P. (09) PI. vii. 



