1880] Notes on the Flowering of Saxifraga sarmentosa. 573 
possible, as may be seen by studying Fig. 1, which represents a 
real case, or by referring to the table and noting the conditions of 
the flowers on April 11th, 16th, etc. As was remarked by the 
writer in a previous article (zzde this journal, Jan., 1879) there is 
nothing in the structure of most dichogamous flowers to prevent 
this, or even to make cross-fertilization between different plants 
any more probable, except as we postulate some fixed uniform 
habit in most insects visiting such plants." 
-In the plant under consideration, however, we find a plan to 
insure cross-fertilization between flowers on different plants, no 
matter in what order insects visit the flowers. This may be 
briefly shown, by referring to the table representing the order of 
flowering. It will be seen, with the exception of the flowers on 
the eighth and ninth branches, which are clearly abnormal, and 
from their position have little part in the general economy of the 
plant, that each set of flowers first pass four or five days as 
staminate flowers, then one to three days as pistilate flowers 
before the next set mature any stamens. Thus the first chance is 
invariably given to the pollen of another plant. If that is not 
secured, the pistils are then likely to be fertilized by the pollen of 
the flowers of the next set upon the same plant. Query: Do 
other plants with cymose panicles present similar cases ? Clearly, 
therefore, is the conclusion impressed, that the more diverse the 
circumstances of the flowers the greater the advantage of cross- 
fertilization. Is cross-fertilization nature’s plan for distributing 
the advantages resulting from a favorable locality to all the indi- 
viduals of a species, or, on the other hand, neutralizing the evils 
of a disadvantageous position? Does it render species more 
uniform ? 
There remain two or three facts concerning the development of 
the petals and stamens which demand explanation. We cannot 
see how their. existence is of the least advantage to the plant. 
Why should one of the lower petals be longer than the other ? 
_Or, if we might attribute so much to accident, why should there 
be regularity about it? May it be that the petal is longer on - 
-the side toward the branch because there is a greater amount 
-9f nourishment passing on that side to supply the branch, and a 
Proportionate amount is conveyed onward to the flower ? 
May not a similar relation explain why the stamens on the 
Cf. an abstract of a paper by Mr. A. S. Wilson in Am. Nat., Vol. XH, p. 39. 
