102 Muhlenbergia, Voluine 4 
“Closely connected with morphologic difference is the ques- 
tion of the absence of intermediate forms. . . At best, it has 
regularly been a question of intermediate forms in the herbaria 
and not in the field.” 
“The constancy of a structure from one generation to an- 
other, or from one habitat to another has been given little atten- 
tion in species-making. Yet it is precisely these which are of 
fundamental importance.” | 
The ecologist “‘sees three critical facts in the development 
of a new species or any new form: (1) ancestry, (2) habitat or 
method of origin, (3) structural changes, very rarely functional 
ones. None of these can be studied adequately anywhere but 
on the ground.” 
Under “Ecologic Procedure,” it is stated that “experiment 
should proceed whenever possible along three parallel lines, 
which have been designated as (1) natural experiments, where 
advantage is taken of natural movements into new habitats, (2) 
habitat cultures, where reciprocal plantings are made in origi- 
nal and new habitats, and (3) control cultures, where the exper- 
iments are carried on in plant-houses, where they can be con- 
trolled or directed at will.”’ 
He suggests an evolution herbarium, in which may be 
found the “record of field observations and experimental results. 
A species or a form will be represented iu it by all the varia- 
tions that can be discovered, and each variation bya large num- 
ber of individuals. The new forms produced by nature, and by 
experiment in nature or under control, will likewise be ade- 
quately represented. This representation will take the form 
not only of the usual dried specimen, but of photographs, draw- 
ings, slides, preserved material, etc.” 
Under “Nomenclature and Treatment of New Forms,” the 
question of ancestry is brought up. ‘When the form bears the 
distinct stamp of sun or shade, of a wet or dry habitat, or of 
hybridation, etc., our search is narrowed at once to deciding 
what species gives the most promise of being the parent form.” 
