Cheeseman. — Notes on the Fertilization of Glossostigma. 355 



to avoid touchiug the upper part of the style, which would then move back 

 and expose the anthers. On retiring, the insect would in all probability dust 

 itself over with pollen, but it would not by this effect the fertilization of the 

 flower, as the stigma would then be closely applied to the upi^er lip of the 

 corolla, — entu'ely out of its path. But let the same insect visit a second 

 flower, and it is then every way hkely that some of the pollen would be 

 rubbed off by the stigma, which as we have seen, would be naturally 

 touched on the first entrance of an insect. I have not been able to syste- 

 matically watch the flowers so as to ascertain what species are instrumental 

 in transferring the pollen, but I have twice observed small Diptera engaged 

 in sucking the flowers. Several of these I caught, and found grains of 

 pollen on the foreheads of some of them. The common red ant is often 

 found crawling over the plant, and I have seen one emerge from a flower 

 with the front of its head thickly covered with yellow pollen, thus proving 

 that this species may play no unimportant part in the fertilization of the 

 plant. Their visits would not, however, be so beneficial as those of winged 

 insects, which would be more likely to bring pollen from distinct plants, 

 and thus effect a more advantageous cross. 



Late in autumn the plants are usually covered with capsules, so 

 that, if fertilization is chiefly performed by insects, they certainly fulfil 

 then* duties in an effectual manner. In old flowers that have been seldom 

 visited it often happens that pollen drops from the anther-cells on to the 

 face of the style bent down just below ; and I perhaps too hastily concluded 

 that self-fertilization would thus inevitably take place if from any reason 

 the flowers were not visited by insects. I did not, until almost too late in 

 the season, pay sufficient attention to the difference existing between the 

 two surfaces of the expanded portion of the style ; and I am now inclined 

 to believe that only one is stigmatiferous — the posterior one, or that turned 

 to the back of the flower when the style is erect, and to the front when it 

 is curved over the stamens. Certpinly this surface alone possesses well- 

 developed stigmatic papiUse, and on it alone have I been able to observe the 

 development and intrusion of the pollen-tubes. If this view is correct, 

 self-fertilization would be almost, if not altogether, impossible. 



The movements of the style in Glossostigina form the most curious 

 example of irritability in the female reproductive organs of plants that I 

 am acquainted with, excepting that produced by a slight touch on the 

 gynostemium of Stylidium. The closing together of the two arms of the 

 style in 2Iimidus and allied genera is analogous ; but in the case of these 

 plants the movement is rarely through a greater angle than 60° or 70°, and 

 is usually much less ; while in Glossostigma the point of the style moves 

 through an arc of at least 180°. On referring to the description given by 



