6 



include the Conifers, the Cycads, and Gnetacece. 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, Muscineee, Vascular Crypto- 

 gams, Phanerogams. As far as the evidence of the rocks 

 goes, it is also, on the whole, that of their first appearance in 

 past time. To speak quite exactly, the remains have been 

 found as follows : Alga3 are the earliest ; Vascular Crypto- 

 gams then appear in company with Gymnosperms and a 

 few Monocotyledons ; then comes the culmination of the 

 Grymnosperms 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 algee of the most remote 

 age, and, moreover, ultimately from the simplest forms of the 

 algse, the Oscillatoriacece, 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 Algae and Mosses, 

 between Mosses and Vascular Cryptogams, between Vascular 

 Cryptogams and Phanerogams. Even if such links were found 



