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The Mesozoic Flora preserved on the whole a very uniform 

 general character from the Rhaetic up to the Neocomian. But 

 after the Lower Greensand there came a complete change, due to 

 the successful usurpation by the true flowering plants. It is the 

 earlier flora, in which the old families were still dominant, of 

 which I propose to speak on the present occasion. 



These old plant families of the Mesozoic age included Horse- 

 tails, already much shorn of their Palaeozoic glories, a few Club 

 Mosses, still more reduced, a vast abundance of Ferns, and, among 

 seed-bearing plants, a great number of Conifers, and various 

 members of the strange race of the Maidenhair Trees, now only 

 represented by a single surviving species, itself scarcely known in 

 this wild state. 



But, in a broad sense, the Secondary Period might be 

 described as the Age of Cycads, a group now so dwindled as to be 

 unfamiliar to those who are not botanists. Some reference was 

 made to the existing family of Cycadaceae in my 1910 address. 

 They are now a small tropical and sub-tropical family of nine 

 genera and about 100 species — handsome palm-like plants some- 

 times reaching the stature of trees. They have no affinity with 

 Palms, but rather with Conifers, though so different from them 

 in habit. The sexes are separated on distinct plants ; the usual 

 fructification is a simple form of cone, while in Cycas itself the 

 seeds are borne on leaf-like carpels growing on the main stem. 

 Throughout all the earlier part of the Mesozoic Age, plants of 

 the Cycad type were extraordinarily abundant in all parts of the 

 world, forming from one half to one third of the land vegetation, 

 and in fact holding a place comparable to that which the 

 Dicotyledons occupy in the living Flora. But among this great 

 mass of Cycad-like plants only a very few are found to have had 

 the simple fructification of true Cycadaceae. The vast majority, 

 while agreeing with modern Cycads in their vegetative organs, 

 possess a totally different and much more advanced reproductive 

 apparatus. 



The true nature of the dominant type of Secondary 

 Cycadophytes was first revealed by the Isle of Wight fossils, and 

 especially Bennettites Gibsonianus found at Luccombe Chine, near 

 Shanklin, in the Lower Greensand. about the year 1856. Our 

 knowledge of the structure of this remarkable fossil, which has 

 proved so important to students of evolution, is due, in the first 

 instance, to the classic investigations of Carruthers, and subse- 

 quently to the work of a distinguished German botanist, Count 

 Solms-Laubach. The structure of the stem, enclosed in an armour 

 of persistent leaf-bases, is in essentials that of a recent Cycad, 

 and from indirect evidence, derived from other specimens, there is 

 no doubt that the habit of the plant was also Cycadean. But, 

 when we come to the reproductive organs, everything is different. 

 The pear-shaped fruits are borne laterally on the stem, closely 

 wedged in among the bases of the leaves. They have a complex 

 structure. The short, thick stalk expands at the top into a dome- 



