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include the Conifers, the Cycads, and Gietacew. Their flower 
is a true flower, but of a very simple type: a perianth is nearly 
always wanting, the sexes are always separate, the floral axis 
is often a real shoot and sometimes even branched, and finally 
the ovules are not contained in an ovary. The woody stem, 
however, of the Conifers is of a higher type than anything we 
have yet met with, having annual rings of growth and a 
distinct bark. It is usually said to approach the dicotyledonous 
type; but, as it is Incomparably the older, it would be more 
strictly correct to say that the dicotyledonous type represented 
by our oaks and elms is a more highly differentiated form of 
the gymnospermic. Lastly, we have the Angiosperms, in which 
the ovules are enclosed in an ovary. ‘They are divided into 
Monocotyledons and Dicotyledons, and comprise all the familiar 
flowers, shrubs, and trees which surround us, and on which 
we need dwell no further. 
3. General Inference from Fossil Plants.—The order in 
which we have taken these four groups is that of their 
respective simplicity, Thallophytes, Muscineze, Vascular Crypto- 
gams, Phanerogams. As far as the evidence of the rocks 
goes, it 1s also, on the whole, that of their first appearance in 
past time. To speak quite exactly, the remains have been 
found as follows:—Algz are the earliest; Vascular Crypto- 
gams then appear in company with Gymnosperms and a 
few Monocotyledons; then comes the culmination of the 
Gymnosperms in the Cycads ; finally, the Dicotyledons emerge 
abruptly in the upper chalk. Fungi lichens and mosses are 
too soft to stand any chance of being preserved in the older 
rocks. So far then, as the record goes, it agrees with the 
natural arrangement. given above. Now the Theory of Descent 
requires that the varied plants of the present epoch, trees, 
shrubs, and herbs, ferns, mosses, and seaweeds, should all 
alike be lineally descended from the alge of the most remote 
age, and, moreover, ultimately from the simplest forms of the 
algee, the Oscillatoriacee, which alone, as far as our knowledge 
goes, can live in hot water, and could, consequently, have 
flourished in the half-boiling ocean of the dim past. The 
rocks, accordingly, should present us with a series, more or 
less complete, of these supposed ancestors of existing plants. 
Is this the case? ‘To this question there is only one answer. 
Had we to consider only the fossil plants of the rocks, so far as 
known, no one in his senses would have been led to such an 
hypothesis. It would never have suggested itself to a botanist. 
No transitional forms are known between Alezw and Mosses, 
between Mosses and Vascular Cryptogams, between Vascular 
Cryptogams and Phanerogams. Lven if such links were found, 
