INTRODUCTION gi 



beginning of a line of ancestors leading on to the 

 Angiosperms, a still higher group. 



The Mesozoic rocks bring us indeed to a period 

 when Gymnosperms were in the making, and attained 

 a high state of development. The Palaeozoic was the 

 age of the most primitive plants, and at its close of 

 the Vascular Cryptogams, especially characteristic of 

 the Devonian, Carboniferous and Permian. At the 

 close of this period, a southern continent was in exis- 

 tence, Gondwanaland with a flora like the two last, but 

 differing in character in the Northern Hemisphere 

 from the Southern type, characterised by Glossop- 

 teris. 



In the British Isles we have no Muschelkalk, but 

 abroad in this formation, and in the latter Trias 

 (Bunter, Keuper and Rhaetic) there was a develop- 

 ment of Cycad-like plants. The Horsetail types and 

 their allies were more closely related to the present- 

 day forms. Lycopods were not abundant. The flora 

 was more xerophytic than in the later part of the 

 Palaeozoic era. Conifers were more abundant. In 

 the Rhaetic beds there are also new types of ferns 

 which connect this period with the succeeding Lias, 

 as do the Araucaria-like Conifers. The Lias itself is 

 remarkable for the development of the latter, and the 

 Cycad-like types, some of which recall the later 

 Bennettites. 



It is in the Jurassic that we meet with an abun- 

 dance of Cycads, and Ginkgo, an extraordinary type 

 represented to-day by the Maiden-hair Tree of Japan, 



