138 MR ROBERT KIDSTON ON THE FRUCTIFICATION OF 



On the specimens of Z. delicatula, Sternb., sp., figured in the Quart. Jour. 

 Geol. Soc, vol. xl. pi. xxv., the development of the fruit can be traced. It at 

 first consists of a globular indusium, which at maturity splits into four valves 

 for the dissemination of the spores. 



On the other hand, what I regard as the true interpretation of the fruit of 

 Calymmatotheca is that which was first propounded by Renault * and more 

 fully explained and illustrated by Zeiller, t viz., that in Calymmatotheca the 

 fruit consists of a number of exannulate sporangia, arranged around a common 

 point of attachment. 



In the case of C. (Sorocladus) aster oides, Lesqx.,j there can be no doubt 

 that the component parts of this star-like fructification are sporangia, and not 

 thong-like segments of a split involucre. 



In his last work, Die Carbon-Flora der Schatzlarer Schichten,§ Dr Stur 

 freely criticises my remarks on his genus Calymmatotheca as employed by him 

 in his Zur Morph. u. Syst, d. Culm- u. Carbonfarne, and still adheres to his 

 original opinion that the portion of the fruit of Calymmatotheca with which we 

 are acquainted, is the thong-like remains of a split indusium. He also mentions, 

 in regard to his C. Stangeri, that he has observed in a few cases at the base of 

 the beaker -like indusium, small convex elevations. 



Notwithstanding this, I still think that Dr Stur is mistaken in his interpre- 

 tation of the fruit of Calymmatotheca, and that in C Stangeri the fruit consists 

 of a number of sporangia arranged around a common axis, as in C. [Sorocladus) 

 aster oides, Lesqx., C. {Sjrfieitojrteris) bifida, L. & H., and C. affinis, L. & H., sp., 

 to be presently described. The small elevations at the base of the inner cavity 

 of the indusium (?) of C Stangeri, to which Dr Stur again refers in his Carbon- 

 Flora,^ have, I am afraid, no organic connection with the fruit, and are perhaps 

 due to mineralisation or to the adhesion of some extraneous matter. I make 

 this suggestion from an examination of the fruit of C. {Sphenopteris) bifida, 

 L. & H., and C. {Sylienopteris) affinis, L. & H., which are similar in all external 

 respects to Stur's Calymmatotheca; and as in these cases the fruit is certainly 

 not composed of thong-like segments of a split indusium, but of true exannulate 

 sporangia, I am induced to believe that Dr Stur, through imperfect preserva- 

 tion of his specimens, is mistaken in their interpretation. 



* Cows d. Botan. Foss., Troisieme Aunee, p. 198, 1883. 



f Ann. d. Scienc. Nat., 6 e s6r. Bot., tome xvi. p. 182, pi. ix. figs. 10, 11. 



% Lesquereux, Rf.pt. Geol. Survey of Illin., vol, iv. p. 406, pi. xiv. figs. 6, 7 ; Coed Flora of Pennsyl, 

 p. 328, pi. xlviii. fig. 9; see also Zeiller, Ann. d. Scienc. Nat., loc. cit., p. 182, pi. ix. figs. 10, 11. 



§ Abhandl. d. 7c. Jc. geol. Reichsanst. , Band xi. Abth. 1, p. 239, Wien, 1885. It is to be regretted 

 that Dr Stur here accuses M. Zeiller of writing anonymously my Review of his Carbon-Flora, contri- 

 buted to the Geol. May., which communication M. Zeiller had neither seen nor was aware of, till after 

 its publication — especially as the paper more fully explaining my views on this subject was published 

 in the Quart. Jour. Geol. Soc, Aug. 1, 1884. 



|| Loc. cit., p. 238. 



