310 O. Feistmantel— Contributions towards the [No. 4, 



Already at that time this author supposed that the leaflets of Spheno- 

 phyllum could have been produced by coalescence of leaves of the genus 

 Aster 'ophyllites, just as in JEquiseturn and in Schizoneura, wherein the 

 spathes or portions of the spathes are produced by the junction of 

 several leaflets ; but in the latter genera we find the spathe traversed 

 by simple veins only, representing the same veins as were in the separate 

 leaflets before these grew together. 



In Asteropliyllites also we have undivided veins in the leaflets. 

 Sphenophyllum, however, has repeatedly forked veins : invariably two or 

 more main veins, originating at the base of the leaf, are continually forked 

 until they reach the margin, so that from the two main veins we can have 

 as many as 20—30 forked veins reaching to the margin in one leaflet. 



But that which Mr. Williamson three years ago advanced as a suppo- 

 sition only he brought forward as an established fact before the last meet- 

 ing of the British Association at Glasgow,* saying that the wedge-shaped 

 leaves of Sphenophyllum are merely the result of the coalescence of several 

 of the leaves of Asteropliyllites. 



The learned author, -who at that meeting expressed also his "strong 

 convictionf that the flora of the coal-measures would ultimately become 

 the battle-field on which the question of evolution with reference to the 

 origin of species would be fought out," will certainly excuse me, taking 

 especially our Indian Sphenopliyllum into consideration, for entertaining 

 some doubts as to the close relationship of Sphenophyllum and Astero- 

 pliyllites in the above-mentioned sense. 



As our figure (PL XV, Fig. 2«) plainly shows, the veins of our Spheno- 

 phyllum pass out as two main veins and are forked in a regular way until 

 they reach the margin. Here no coalescence of leaflets is possible, least 

 of all of Asteropliyllites where the leaflets have only one undivided midrib. 

 Further, everybody knows very well that the leaflets of Asteropliyllites 

 are linear and attenuated both towards the base and towards the apex, so 

 that they could never produce by their coalescence a wedge-shaped leaf, 

 with the broadest portion just at the apex as in Sphenophyllum. .. 



Our SphenopliyUum shows this further to be quite impossible by the 



arrangement of the leaf -whorls in the articula, as we always find quite 



regularly three pairs of leaflets, of which one pair is smaller than the others. 



The stalk also is generally thinner in the genus SphenopliyUum, our 



Indian form showing this very evidently. 



If the leaflets of Asterophyllites were to grow together, they would 



* I have read the report published in Nature for 21st September, 1876, No. 360, 

 p. 455, the only one which has as yet reached us. 

 t Ibidem, p. 456. 



