CONCLUSION 89 



with the unknown forms which he unearths. On the 

 other side of the systematist stands the experimentalist, 

 with his hybrids, varieties, and mutations, and offers a 

 warning against holding any species as an immutable 

 thing. A reminder that all the binomially named 

 species in our text-books and floras are established 

 only in a relative sense, for, since man's history began, 

 new forms have arisen and taken their place in the 

 ranks of those which "breed true," and therefore should 

 be considered true species. From these branches of 

 botany we get, if not cut and dried ideas on evolution, 

 at least suggestive and stimulating ones. The morph- 

 ologist, anatomist, and physiologist are chiefly concerned 

 with the question of how plants live to-day, and the 

 manner in which their mechanisms are adapted to the 

 conditions in which they find themselves, and the way 

 the delicate machine is balanced and adjusted. These 

 living individuals the ecologist sees in communities, 

 with inter-relations between the different members and 

 adaptations to their conditions of environment. The 

 results from all these studies again reflects light on the 

 problems of the palseobotanist, for the plants of the 

 past were also individuals, breathing, assimilating, with 

 organs differing only in details from those of modern 

 plants ; and they also lived in communities. This works 

 out like a sum in algebra with an unknown factor, for 

 of the fossils there are only the anatomical and mor- 

 phological features left, while of living plants these are 

 available combined with experimental work on their 

 physiological and ecological bearings. The relation 

 between these being discovered in modern plants we 

 can draw the conclusions about the conditions of the 

 past communities. Here not many details have yet 

 accumulated, but the work promises well, and it opens 



