4 



THE DEVELOPMENT OF THE SPORANGIUM OF 



LYG ODIUM 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABOILA.TORY, lOI 



R. BiNFORD 



(with THIRTY-SEVEN FIGURES) 



In his ''Studies in the morphology of spore-producing members'' 

 (No. IV), Bower suggests a line of evolution from the Marattiaceae 

 to the Polypodiaceae, with the Osmundaceae, Schizaeaceae, Glei- 

 cheniaceae, Cyatheaceae, Hymenophyllaceae, and related forms as 

 representatives of intermediate types. The Marattiaceae and Poly- 

 podiaceae are well-worked groups, but the intermediate forms are 

 not so well known. Lygodium; one of the Schizaeaceae, has been 

 chosen, therefore, for the present study. 



In his classical work on this family, Prantl^ considered the 

 morphology and the taxonomy of the whole family. His description 

 of the sporangium of Lygodium is here verified except in one point, 

 which will be mentioned later. The present work calls attention to 



r 



some points that have not been noted in other studies and emphasizes 

 some that have been quite neglected. 



The material of the present study came from the Philippine 

 Islands and was collected by Dr. H. N. Whitford on Mount Mari- 

 vcles, Province of Bataan, Luzon, and was sent to the University of 

 Chicago for demonstration purposes. The species described in the 

 paper is L. circinatum; but L. flexuastitn was also examined and found 

 to be somewhat less variable. 



Arrangement and 



sporan 



ct 



two rows on the ventral surface of the fertile lacinia, and are solitary, 

 i. e., there is only one sporangium in a sorus; Prantl calls this a 

 monangial" sorus. The indusium grows out around the spo- 

 rangium so as to form a pocket open toward the apex on the ventral side 



I Untersuchungen zur Morphologic der Gefasskryptogamen. 2. Heft- Die 

 Schizaeaceen, morphologisch irnd systematisch bearbeitet. Leipzig. 1881. 



Botanical Gazette, vol. 44] ]2i4 



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