FERTILIZATION IN THE VEGETABLE KINGDOM. 229 



by the astonishingly small quantity produced by cleistogene 

 flowers, which lose none of their j^ollen, in comj)arison with 

 that produced by the open flowers borne by the same plants ; 

 and yet this small quantity suffices for the fertilization of all 

 their numerous seeds. Mr. Hussall took pains in estimating 

 the number of pollen-grains produced by a flower of the Dan- 

 delion, and found the number to be 243,600, and in a Peony 

 3,654,000 grains. The editor of the ' Botanical Register ' 

 counted the ovules in the flowers of Wistaria sinensis^ and 

 carefully estimated the number of pollen-grains, and he found 

 that for each ovule there were 7,000 grains." — (pp. 376, 377.) 



These are probably fair averages of the numerical ratio 

 of pollen to ovules in flowers which are adapted to be fertil- 

 ized by insect agency. Their meaning in the " economy of 

 nature " is seen by a comparison on the one hand with ane- 

 mo'pliiloiis^ i. e. wind-fertilized, flowers, in most of which there 

 is a vastly greater disproportion between the numbers, — com- 

 pensating for inevitable waste, — and on the other hand with 

 cleistogenous flowers, namely, those small and less developed 

 blossoms which some plants produce in addition to the ordi- 

 nary sort, and which fertilize as it were in the bud, necessarily 

 by their own pollen. Here is no waste, and accordingly the 

 anthers are very small, and the pollen-grains are not many times 

 more than the ovules : also such flowers are never brightly 

 colored, never odoriferous, and they never secrete nectar. 



The only advantages of this close-fertilization which we 

 can think of are sureness and strict likeness ; both of which 

 are quite as well secured by budding-reproduction. Now, as 

 cleistogene flowers are borne, we believe, chiefly and perhaps 

 only, by species whose normal blossoms are adapted for insect- 

 fertilization, they must be regarded as a subsidiary arrange- 

 ment, a safeguard against failure of proper insect-visitation. 

 As the volume before us amply shows, this failure is in gen- 

 eral provided for by a more or less wide margin of self-fertil- 

 ization in the very flowers which are adapted for crossing. In 

 Impatiens, Yiola, and the like, it is provided for by separate 

 flowers, the sj^ecial adaptations of which are unmistakable. 



H. Miiller appears to have shown " that large and conspic- 



