50 
A. H Church . 
correct plant description will he found in the accurate presentation 
of the problems of leaf arrangement or Phyllotaxis. 
The study of Phyllotaxis is so closely hound up with the 
History of the Spiral Theory that it is often necessary to point out 
that spiral phyllotaxis still exists in the vast majority of vegetative 
shoots, whether one accepts any Spiral Theory or not. Because 
the Spiral Theory of Schimper completely failed to explain the 
phenomena of the comparatively rare case of Dorsiventral 
Symmetry, it does not follow that all conceptions of spiral growth 
are to be thrown overboard, and that one must accept the dictum 
of Sachs that there is “no general law which can be formulated for 
the arrangement of organs on a parent axis.” Not only is spiral 
symmetry a perfectly definite phenomenon, but it becomes 
increasingly clear that it for some reason actually represents the 
phylogenetically primitive type of growth; and though exception 
may be taken to the view that all centrically symmetrical types of 
construction are necessarily derived from spiral growth-forms, no 
one will be disposed to deny that the case of dorsiventral flower- 
shoots is always phylogenetically a secondary phenomenon, and 
that here as in dorsiventral vegetative shoots every transition to a 
more and more perfect attainment of this special type of symmetry 
is observable. The general law which controls the distribution Of 
plant members must certainly include these special cases; but in its 
primary significance it must be founded on the most widely 
distributed case. 
The discussion of the elimination of the Spiral Theory of 
Schimper from modern morphology, with which it is still closely 
interwoven, for want of something better, in every elementary text¬ 
book, demands the consideration of the different standpoints of the 
old morphology and the new with regard to the plant as an object 
to be scientifically described. 
To the older botanists, the morphologists of the Eighteenth 
Century, and so long in fact as Botany remained dominated by the 
doctrine of Constancy of Species, the subject of morphology 
presented a very simple ideal. So long as every species was 
regarded as a definite creation, and every individual member of the 
species the mere working out of a replica of the parent, morphology 
dealt solely with adult structures. The study of form became 
restricted to the formal account of the framework of the adult 
organism, its fully matured stem, leaves, flowers and fruit; all 
