534 PROCEEDINGS OF THE SOCIETY. 



existing yews. A microscopic study of well preserved and authentic 

 specimens of this fossil led him (the President) to publish a paper in 

 the Society's Journal in 1872 in which, with the assistance of admirable 

 plates, he demonstrated that this stem was that of a cellular plant be- 

 longing to the Algae — a view at first strongly contested by Sir Wm. 

 Dawson, but at length accepted. Fungal remains had also been detected 

 in the Carboniferous strata by Alder, in the form of masses of myce- 

 lium in the shale, and also by himself as parasites penetrating the 

 tissues of higher plants. The plants which, by their external form and 

 internal structure, have been certainly determined, are vascular plants 

 belonging to the EquisetaceaB, Filices, and Selaginellaceae amongst 

 Cryptogams, and to the Coniferae, groups which exist in the present 

 flora of the globe, and are represented in the indigenous flora of 

 Britain. 



I. The Equisetaceae are herbaceous plants with underground stems 

 and ascending leaf- and spore-bearing stems ; the leaves are reduced to a 

 tooth-sheath at the nodes ; the fruit is in small cones consisting of 

 stalked peltate leaves on a shortened axis, each leaf or sporophore 

 having several sporanges attached to the flat apex. The spores are small 

 and of uniform size, and are furnished with hygrometric elaters. In all 

 essential characters the living plants agree with the Carboniferous 

 Equisetaceae ; but these ancient plants had arborescent stems, distinct 

 leaves, and cones composed of alternate whorls of sporophylls and bracts. 

 Like other Vascular Cryptogams of the period, the stems increased in 

 diameter through the oresence of a cambium which added to the circum- 

 ference of the vascular cylinder, just as the wood cells are produced in 

 the higher exogenous stems of the present flora. 



The structure of the cone was essentially the same in the living and 

 the fossil EquisetaceaB, and this was the case also in regard to the struc- 

 ture of the sporanges and the character of the spores. 



II. Filices are represented at the present time in England by herba- 

 ceous plants, some of which, like the male fern and Royal fern, have 

 stems ; but such stems attain a great size in the tree ferns of warmer 

 regions. Seme ferns have very simple leaves, but others have the most 

 compound leaves found in any plants. The sporanges are borne on the 

 under side or margins of the leaves, the spores being uniform in size. 

 The Carboniferous ferns included many that could not be separated from 

 living groups ; but in addition there were two extinct groups repre- 

 sented by Psaronius, and by the more remarkable stem of Heterangium, 

 which, as in Calamites, possessed a cambium by which additions were 

 made to the circumference of the vascular cylinder. 



III. Selaginellaceae are common in the existing flora, though repre- 

 sented in Britain by a single species, a small plant, some 2 or 3 in. 

 high, which like the others included in the order, is mainly distin- 

 guished from the closely allied Lycopodiaceae by possessing two kinds 

 of spore, macro- and microspores. The Carboniferous representatives 

 were huge trees with large leaves and an exogenous stem as in the 

 Calamites, and a larger cone than in the living species, but agreeing 

 in the important details with those of living plants. These plants 

 attained a great height, and, with the Calamites, supplied the chief 

 materials of our coal-beds. 



