



Chap. III. MENYANTHES TRIFOLIATA. 115 



grains from the two forms not differing in diameter in any 

 appreciable degree, there can hardly be a doubt from the 

 great difference in the two forms in the length of the pistil, 

 and especially of the stigma, together with its more papil- 

 lose condition in the short-styled form, that the present spe- 

 cies is truly heterostyled. This case resembles that of 

 Linum grandiflorum, in which the sole difference between 

 the two forms consists in the length of the pistils and stig- 

 mas. From the great length oi the tubular corolla of Leu- 

 cosmia, it is clear that the flowers are cross-fertilised by 

 large Lepidoptera or by honey-sucking birds, and the posi- 

 I tion of the stamens in two whorls one beneath the other, 



which is a character that I have not seen in any other 

 heterostyled dimorphic plant, probably serves to smear the 

 inserted organ thoroughly with pollen. 



MENYANTHES TRIFOLIATA (GENTIANEiE). 



This plant inhabits marshes : my son William gathered 

 247 flowers from so many distinct plants, and of these 110 

 were long-styled, and 137 short-styled. The pistil oi the 

 long-styled form is in length to that of the short-styled in 

 the ratio of about 3 to 2. The stigma of the former, as 

 my son observed, is decidedly larger than that of the short- 

 styled; but in both forms it varies much in size. The 

 stamens of the short-styled are almost double the length of 

 those of the long-styled ; so that their anthers stand rather 

 above the level of the stigma of the long-styled form. The 

 anthers also vary much in size, but seem often to be of 

 larger size in the short-styled flowers. My son made with 

 the camera many drawings of the pollen-grains, and those 

 from the short-styled flowers were in diameter in nearly the 

 ratio of 100 to 84 to those from the long-styled flowers. I 

 know nothing about the capacity for fertilisation in the 

 two forms; but short-styled plants, living by themselves 

 in the gardens at Kew, have produced an abundance of cap- 

 sules, yet the seeds have never germinated; and this looks 

 as if the short-styled form was sterile with its own pollen. 



LlMNANTHEMUM INDICUM (GeNTIANE^). 



This plant is mentioned by Mr. Thwaites, in his Enu- 

 meration of the Plants of Ceylon, as presenting two forms ; 



