JOUKNAL 



OF THE 



ROYAL MICROSCOPICAL SOCIETY. 



APRIL, 1905. 



TRANSACTIONS OF THE SOCIETY. 



II. — Tlie President's Address : What were the Carboniferous Ferns ? 

 By Dukixfield H. Scott, F.E.S. 



(Bead January 18, 1905.) 

 Plates I. to III. 



The Flora of the Carboniferous Period, as commonly portrayed, is 

 characterised by the presence of five great groups of vascular 

 plants : the Equisetales (Horse-tails) ; the Lycopods (Club-mosses) ; 

 the Sphenophylls (intermediate in some respects between the two 

 former groups) ; the Ferns ; these four classes have been widely 

 accepted as cryptogamic, spore- bearing plants, though other views 

 have been held, from time to time, as to the position of some 

 of their members. The fifth group was that of the Cordaite?e, 

 highly organised, seed-bearing trees, to some extent combining the 

 characters of the Conifers and Cycads of the recent Flora, and 

 allied to that isolated species the Maidenhair- tree (Ginkgo biloba) 

 of China and Japan. 



Of all these groups that of the Ferns, commonly so-called, is 

 by far the most important in number of species, amounting to 

 about half of the total known Flora. Thus Brongniart, in 1849, 

 estimated the whole Pala?ozoic Flora then known at 500 species, of 



EXPLANATION OF PLATE I. 



Fig. 1. Sphenopteris ohtusiloba. Portion of frond, probably of one of the Pteridc- 

 sperniese. From a photograph by Mr. W. Hemingway. 

 „ 2. Pecopteris abbreviala. Portion of frond of a Marattiaceous Fern. From a 

 photograph by Mr. W. Hemingway. 



April 19th, 1905 L 



