Origin and Development of the Composites. 3 
Linnean species has not yet been effected, changes in the 
individual in response to definite factors of the environment have 
been obtained which certainly give greater differences than those 
between a very large number of taxonomic species. 
Some instances have already been mentioned of the effect of 
injury, food supply etc., on the floral characters: see Molliard (IV, 
55-56a) and his explanation of the dioecism of Pulicciria (II, 26), 
also Daniel (IV, 23-24) and the reduction of doubling, Chapter IV, 
C, under Causal Morphology, 
The value of this type of work is recognised by Massart (53), 
who considers that the effects of the environment are hereditary in 
some cases at least and, as a consequence, recognises the 
possibility of a polyphyletic origin for genera or even species. 
Warming (71, Chap. 100) and the Reports of the Carnegie 
Institution of Washington furnish abundant references to such 
experimental evolution. The last chapter of Warming’s Oecology of 
Plants is of great interest in this connection (see below Chapter XI). 
An important point is developed by Harshberger (35) under the term 
“ generic coefficient,” which expresses the percentage relation 
between the number of genera and that of species in any region : i.e. 
numbei of genet a x iQ0=generic coefficient. Simple topography, 
number of species r b 
as on the plains, gives a high generic coefficient, while the highly 
diversified topography of regions such as the Rockies and Andes 
gives a low generic coefficient. 
The subject cannot be dealt with in detail here, but it may be 
useful to bring together some references. Taylor (70) mentions 
habitat endemics. Cockayne (17) uses the term epharmonic 
variation in the sense of “ a change in its form or physiological 
behaviour beneficial to an organism evoked by the operation of 
some environmental stimulus. Such a change may be called 
epharmonic adaptation, as distinguished from such adaptations as 
cannot be traced to any direct action of the environment” 
Foweraker (26), who gives some experiments on anthocyan changes 
in Raoulia in response to environment, suggests natural selection as 
the cause of the origin of cushion-plants but he agrees, in conversation 
with the writer, that the most probable explanation of his chief pro¬ 
blem, “What causes this espalier shape?”, lies in the direct action 
of the heat radiation from the sun-baked shingle on the permeability 
of the protoplasm of the cells of the under surface of the lateral 
branches (cp. 68a). This seems to be a clear case of epharmonic 
