PART I.| HISTORICAL INTRODUCTION. 19 
which remain closed (flores cleistogami, Kuhn) and produce seed 
regularly by self-fertilisation. He supposed that the existence of 
cleistogamic flowers was due partly (eg. Lamiwm amplexicaule) to 
low temperature, which hindered the development of the ordinary 
_ flowers, and partly to failure of the insects which under normal 
- circumstances effected cross-fertilisation. 
By this explanation, Axell rectified the conception that was so 
distinctly uttered by Hildebrand and Delpino in their earlier 
writings, viz., that cross-fertilisation is advantageous and self- 
fertilisation disadvantageous for plants, by showing that though 
cross-fertilisation is better than self-fertilisation, yet self-fertilisation 
is infinitely better than absence of fertilisation and consequent 
ee ite aml 
Fia 2.—Cleistogamic and ordinary flowers of Lamium amplexicaule. 
1—4, large ordinary flower, not quite twive natural size. 1, entire flower; 2, oblique view of 
mouth, showing anthers and stigma ; 3, upper part of corolla just before the flower opens ; 4, nectary 
 (n) and ovary (02). 
: 5—10, small cleistogamic flower (5-8, x 5;°9, 10, x 24). 5, entire cleistogamic flower from the 
outer side ; 6, corolla, opened by force, seen from the side; 7, the same, opened less widely, seen 
_ from below; 8, corolla of a cletstoraniic flower, unopened, from below; 9, essential organs of a 
cleistogamic flower undergoing self-fertilisation, two stamens having been removed ; 10, ovary and 
- nectary seen from the front and right. 
sterility; and he also removed by his elucidation of cleistogamic 
' flowers one great objection to the Knight-Darwin law,—the 
argument which was used against it by H. von Mohl. 
Axell founds his attempt to classify all floral mechanisms of 
Phanerogams in the natural order of their development upon two 
laws which he lays down as axioms: (1) Nature strives to increase 
as much as possible the number of individuals in each species ; 
and (2) she strives to attain the greatest possible results by the 
simplest possible means. If, instead of abiding by the teleological 
standpoint which personifies nature, Axell had risen to the 
objective conception of nature which Darwin founded, he might 
c 2 
