^^ Two Kinds of Stamens with Different Functions in the same flower. 



sivelv effected by the pollen of the longer stamens, whilst the shorter stamens 

 scrve only to attract pollen -gathering or pollen-eating insects. It is far from sur- 

 prising that the pollen of these latter stamens, though often produced in large 

 quantity, should tend to degeneration. Darwin long ago came to this conclusion 

 with respect to some Mclastomaceas with differently-coloiired anthers, of which 

 he had raised seedlings from pollen both of the longe and shorter stamens („There 

 is reason to believe that the shorter stamens are tending to abortion." — "Cross- 

 and Self-Fertilisation", p. 298, footnote). The Lagerstrcimia in my garden being 

 seifsterile, I fertilised some flowers with green, and others with )^ellow pollen of 

 a different variety (or species?) growing in other gardens; both produced fruits 

 with apparently good seeds, but only some of those from the green pollen have 

 germinated. 



As in all the flowers above-named, with differently-coloured anthers, the duU 

 colour of those of the longer stamens evidently serves to make them less visible 

 to insects, may not the green colour of the anthers of the long stamens of the 

 mid-styled and short-styled flowers of Lythriim salicaria also protect them against 

 the attacks of pollinivorous insects, to which, from protruding far from the co- 

 rolla, they would be more exposed thän those of the shorter stamens? 



Even without being differently coloured, the stamens of the same flower 

 may be divided into different sets with different functions. Thus in a species of 

 Cassia the visitin g humble-bees gather the pollen of the four intermediate stamens 

 (the three upper ones being pollenless), which are short and straight, whilst the 

 three lower ones are very long and curved in such a w^ay that their pollen is 

 deposited on the back of the humblebees. The pistil is of the same length and 

 curved in the same way as the longer stamens, Another very striking instance 

 has been carefuUy described by Prof. J. E. Todd of Tabor (Iowa) in a plant of 

 a very different family, viz. Solanum rostratiim {American Naturalist, April, 

 1882, p. 281): one stamen and the pistil are very long and strangely curved ; four 

 stamens are short and straight, and serve only to furnish pollen to the visiting 

 insects; all the anthers, as I am informed by Prof. Todd, are of the same dull 

 yellow colour. 



Blumenau, Sa. Catharina, Brazil, December 27, 1882. 



