RARE TREES IX ARBOTSBURY CASTLE GARDENS. 185 



Passing over the earliest forms of vegetable life exhibited in 

 Cellular Cryptogams, Algoe, Lichens, Fungi, I shall mention 

 incidentally the three chief divisions — Vascular Cryptogams, 

 (Ferns, Equisetacere Lycopodiaceje); GymnospermejB, seeds naked 

 (ConiferiB, Cycadese, Gnetacese); Angiospermce, seeds contained in 

 a receptacle, Monocotyledons, having one seed-leaf or cotyledon, and 

 Dicotyledons having two seed-leaves, with a pith and true separable 

 bark and growing by concentric zones. The Conifers appeared for 

 the first time in the Carboniferous age. In the succeeding ages, 

 from the Permian to the Tertiary, they increased largely both in 

 genera and species. There was a marvellous and energetic impulse 

 at the beginning of the Cretaceous age, which brought about the 

 introduction of the monocotyledonous and dicotyledonous plants, 

 which have since developed iuio the different genera and species 

 which now cover the face of the earth. During the lengthened 

 duration of the Tertiary period the world underwent great climatic 

 changes owing to extensive accessions of land and diminution of 

 sea. The union of continents and the extinction of vast inland 

 lakes in Asia, Africa, and Europe, by upheavals of mountain chains 

 and the elevation of land had considerable influence upon the 

 temperature of the globe. These modifications were not accom- 

 plished all at once, but gradually, affording time for those plants 

 which were sufficiently hardy to submit to these changes. During 

 the early Tertiary period {Eocene) tlie climate continued tropical, 

 or at least sub-tropical. In Dorsetshire and the South of England, 

 France, and Northern Italy, are found remains of Palms, both fan- 

 shaped, and pinnate-leaved forms, seeds of Nipa, a plant now only 

 met Avith in the salt-marshes of the coasts and islands of the Indian 

 Seas and the Philippines, Aralias, and Oaks allied to some now 

 growing in the tropics. The numerous plant relics from the 

 London Clay of the Isle of Sheppy equally attest to the tropical 

 character of the flora of that age. Palms of that age can 

 be traced through Northern Germany and Switzerland. Of the 

 fossil plants which can be determined with any certainty, only a 

 few belong to the southern hemisphere ; the rest have their living 



