CONCLUSION 175 



organization. But in height and girth there is little 

 difference between the earliest and the latest trees; there 

 seems a limit to the possible size of plants on this planet, 

 as there is to that of animals, the height of mountains, 

 or the depth of the sea. The "higher plants" are often 

 less massive and less in height than the lower Man is 

 less in stature chan was the Dinosaur and though by 

 no legitimate stretch of the imagination can we speak 

 of brain in plants, there is an unconscious superiority of 

 adaptation by which the more highly organized plants 

 capture the soil they dominate. 



It has been noted in the previous chapters that so 

 far back as the Coal Measure period the vegetative parts 

 of plants were in many respects similar to those of the 

 present, it was in the reproductive organs that the 

 essential differences lay. Naturally, when a race (as 

 all races do) depends for its very existence on the chain 

 of individuals leading from generation to generation, the 

 most important items in the plant structures must be 

 those mechanisms concerned with reproduction. It is 

 here that we see the most fundamental differences be- 

 tween living and fossil plants, between the higher and 

 the lower of those now living, between the forest trees 

 of the present and the forest trees of the past. The 

 wood of the palaeozoic Lycopods was in the quality and 

 extent and origin of its secondary growth comparable 

 with that of higher plants still living to-day yet in the 

 fruiting organs how vast is the contrast! The Lycopods, 

 with simple cones composed of scales in whose huge 

 sporangia were simple single-celled spores; the flowering- 

 plants, with male and female sharply contrasted yet grow- 

 ing in the same cone (one can legitimately compare a 

 flower with a cone), surrounded by specially coloured 

 and protective scales, and with the " spore " in the tissue 

 of the young seed so modified and changed that it is 

 only in a technical sense that comparison with the Lyco- 

 pod spore is possible. 



To study the minute details of fossil plants it is 



