140 THE EVOLUTION OF PLANTS 



the most familiar Ferns, the Polypodiaceae 

 (e. g. Bracken, Male Fern, Hart's Tongue, etc.), 

 have not been found in older rocks than the 

 Jurassic. We will only say a few words on the 

 history of two families which are of special 

 interest the Osmundaceae, or Royal Ferns, and 

 the Marattiacese, tracing them back, as far as 

 possible, to their Palaeozoic source. 



The Royal Fern, a handsome plant, growing 

 in bogs and wet woods and especially common 

 in Ireland, is only too well known, for its popu- 

 larity with collectors and gardeners threatens 

 its extinction in many places. It has an extra- 

 ordinarily wide distribution, extending from 

 Europe to Japan, India, and South Africa, and 

 from Canada to South Brazil. 



In this plant the upper part of the frond is 

 fertile, the leaflets being reduced to mere stalks, 

 crowded with sporangia; the lower part bears 

 the ordinary green leaflets. In other species of 

 Osmunda and even in some forms of 0. regalis, 

 there are separate vegetative and fertile fronds, 

 while in Todea, a Southern Hemisphere genus, 

 there is no distinction at all, the sporangia appear- 

 ing on the under side of unaltered leaflets. 



The sporangia themselves are different from 

 those of most modern Ferns, such as the Bracken, 

 the Male Fern or the Maidenhair. In the latter 

 a single row of thickened cells forms a ring round 



