114 HETEROSTYLED DIMORPHIC PLANTS. Chap. III. 



visited by insects; these are adapted for self -fertilisa- 

 tion, though still capable of cross-fertilisation. Ac- 

 cording to Delpino, the Polygonacese are generally 

 fertilised by the wind, instead of by insects as in the 

 present genus. 



Leucosmia Burnettiana (Thymell-e). 



As Professor Asa Gray has expressed his belief * that 

 this species and L. acuminata, as well as some species in 

 the allied genus Drymispermum, are dimorphic or hetero- 

 styled, I procured from Kew, through the kindness of Dr. 

 Hooker, two dried flowers of the former species, an in- 

 habitant of the Friendly Islands in the Pacific. The pistil 

 of the long-styled form is to that of the short-styled as 100 

 to 86 in length; the stigma projects just above the throat 

 of the corolla, and is surrounded by five anthers, the tips 

 of which reach up almost to its base; and lower down, 

 within the tubular corolla, five other and rather smaller 

 anthers are seated. In the short-styled form, the stigma 

 stands some way down the tube of the corolla, nearly on a 

 level with the lower anthers of the other form: it differs 

 remarkably from the stigma of the long-styled form, in 

 being more papillose, and in being longer in the ratio of 

 100 to 60. The anthers of the upper stamens in the short- 

 styled form are supported on free filaments, and project 

 above the throat of the corolla, whilst the anthers of the 

 lower stamens are seated in the throat on a level with the 

 upper stamens of the other form. The diameters of a con- 

 siderable number of grains from both sets of anthers in 

 both forms were measured, but they did not differ in any 

 trustworthy degree. The mean diameter of twenty-two 

 grains from the short-styled flower was to that of twenty- 

 four grains from the long-styled, as 100 to 99. The anthers 

 of the upper stamens in the short-styled form appeared to 

 be poorly developed, and contained a considerable number 

 of shrivelled grains which were omitted in striking the 

 above average. Notwithstanding the fact of the pollen- 



* 'American Journal of Sci- 'Journal of Botany,' vol. iii-» 

 ence,' 1865, p. 101, and Seemann's 1865, p. 305. 



