102 PHILOSOPHICAL NOTES ON 



we ought somehow to be able to trace their connexion with sea- 

 weeds, their ancestral prototypes. This, I think, we are able to 

 do in a large measure. 



Driven on land, as plants must have been by a keen struggle 

 for life under water, the transition from a wholly water-medium 

 to a wholly air-medium sufficiently explains the difference of 

 texture and vascularity, and other characteristics of land plants. 

 Then the struggle for life on land, driving them again from 

 swampy localities to drained land, and from this to mountains and 

 deserts, sufficiently accounts for the innumerable variations we see 

 in land plants.* 



Ferns — cryptogams themselves — may, I think, be taken as 

 links between seaweeds and phoenogams. 



In the still keener struggle for life on land, we find plants 

 not only occupying very dry and high land, but taking root on 

 other plants, and becoming epiphytes and parasites, such as ferns, 

 fungi, orchids, aroids, amaryllids, bromeliads, dodder, mistletoe, 

 Loranthus, Rafflesia Arnoldii, &c. 



The latter is the most striking of all. The whole plant is the 

 flower only. It has dispensed with stem and leaves. Its root, or 

 what performs the function of root, has become amalgamated with 

 the tissues of the plant on which it feeds — a species of vine. This 

 parasite flower is said to measure nine feet in circumference, and 

 weigh fifteen pounds ! 



"We find other plants so modified as to be able to lead a large 

 part of their life underground. 



If we try to follow mentally the further transition of seaweeds 

 to an air life, with such varying surroundings, we shall not find 

 it so very difficult a task as might at first appear. 



Let us imagine that at first all plants were submerged, that is, 

 surrounded entirely by a water medium ; although suited to a 

 submerged life, tides must have frequently left them uncovered. 

 Their ripe spores, ready for dissemination, would be either 

 scattered by the Avind on to drier land, or during submergence, 

 with the flowing tide, the spores would be carried to the land and 



* It should be remembered that geologists have established the fact that 

 land has altered its altitude many times, and plants on low lauds had to alter 

 to meet the changed surroundings. 



