338 EuG. Warming. 



stamens. But in many homogamous or slightly dichogamous 

 and small-flowered species, self-pollination is a process which 

 regularly takes place, and which produces an excellent 

 result. It is seen here, as in the Greenland Cruciferæ, Saxijra- 

 gæ, etc., that fruit-setting follows immediately after flowering, 

 and that there is a gradual succession of the sizes of the 

 fruits, according to the age of the flowers. 



Polygamy (Pleogamy). Many of the High Arctic, and 

 even small-flowered and homogamous species have poly- 

 gamy, especially gynodiœcism (for instance Cerastium alpi- 

 num, С trigynum, Stellaria longipes, S. borealis, Minuartia 

 biflora, and others, even Arctic species of Melandriiim). Poly- 

 gamy must be regarded as an unfavourable feature where 

 the country is as poor in insects as are the Arctic countries. 



From the preceding detailed descriptions it is evident 

 that few species have hermaphrodite flowers only, and con- 

 tinued investigations will probably result in the reduction 

 of even their number; also probably many more combina- 

 tions of ^, ? and Si than are now known, will be found. 



A peculiarity common to the gynodiœcious species is 

 the varying degree of reduction of the stamens in 

 the female flowers; many examples of this have been mention- 

 ed and figured above. There is every possible degree of reduc- 

 tion of the anthers, according as the development which has 

 once begun, stops earlier or later; I have seen no female 

 flower which was entirely without rudiments of stamens. To 

 this must be added those hermaphrodite flowers in which 

 a few or several stamens are abortive. Several successive 

 stages of more or less decided abortion may thus be demon- 

 strated, and that often in one and the same species. 



Another peculiarity which accompanies the one mention- 

 ed above, is that the corolla is diminished in size more 

 or less in all the female flowers. There are extremely few 



