From this last consideration we pass naturally to a discussion 

 of the nature of the material which may be of use in the study 

 of fluctuating and discontinuous variability. It needs no argu- 

 ment to support the assertion that a successful experimental 

 analysis of the behavior of separate characters may be carried 

 out only when dealing with series of organisms fluctuating about 

 a known mean with a measurable amplitude of variability. 



Systematic species as ordinarily accepted generally consist of 

 more than one independent and constant sub-species, or elemen- 

 tary species which may not be assumed to interbreed or inter- 

 grade, unless actually demonstrated to do so by pedigreed cul- 

 tures. So far, but few elementary species have been found to 

 interbreed. A due recognition of this simple fact would save us 

 a vast amount of pyramidal logic resting on an inverted apex of 

 supposition. 



Again the accumulation of observations upon the prevalence 

 and effect of self- and cross-fertilization has totally unsettled the 

 generalizations current within the last few decades. Briefly 

 stated, a moderate proportion of the flora of any region is au- 

 togamous, a large proportion both autogamous and heterogam- 

 ous, and a moderate proportion entirely heterogamous. The 

 relative number of species included in the categories indicated 

 varies greatly in different regions. To assert the deleterious 

 effects of self-fertilization, of all or a majority of plants, is to base 

 a statement upon evidence that lacks authentication and correla- 

 tion, as has been strikingly demonstrated by recent results. As 

 a matter of fact no phase of evolutionary science is as badly in 

 need of investigation as that which concerns the effects of close 

 and cross-breeding. 



It is also to be said that current misconceptions as to the ex- 

 treme range of fluctuating variability of many native species have 

 arisen from a failure to recognize the composite nature of the 

 Linnacan, or group-species, upon which observations have been 

 based, as I have found with the common evening-primrose. 



The demands of ordinary floristic work are usually met by the 

 formulation of collective s|)ecies, which are in fact, an undeniable 

 convenience, and necessity perhaps, for the elementary teacher and 



