182 HETEROSTYLED TRIMORPHIC PLANTS. Chap. IV. 



sules, containing a larger average of seed, namely, 9.2. 

 These plants, therefore, in function show not the 

 least sign of being heterostyled. I may add that 18 

 flowers protected by a net were left to fertilise them- 

 selves, and only 10 of these (i. e. 55 per cent.) yielded 

 capsules, which contained on an average only 6.3 seeds. 

 v So that the access of insects, or artificial aid in plac- 

 ing pollen on the stigma, increases the fertility of the 

 flowers; and I found that this applied especially to 

 those having shorter pistils. It should be remem- 

 bered that the flowers hang downwards, so that those 

 with short pistils would be the least likely to receive 

 their own pollen, unless they were aided in some 

 manner. 



Finally, as Hildebrand has remarked, there is no 

 evidence that any of the heterostyled species of Oxalis 

 are tending towards a dioecious condition, as Zuccarini 

 and Lindley inferred from the differences in the re- 

 productive organs of the three forms, the meaning of 

 which they did not understand. 



PONTEDERIA [SP. ?] (PONTEDERIACE^E) . 



Fritz Miiller found this aquatic plant, which is al- 

 lied to the Liliacea?, growing in the greatest profusion 

 on the banks of a river in Southern Brazil.* But only 

 two forms were found, the flowers of which include 

 three long and three short stamens. The pistil of the 

 long-styled form, in two dried flowers which were sent 

 me, was in length as 100 to 32, and its stigma as 100 

 to 80, compared with the same organs in the short- 

 styled form. The long-styled stigma projects consid- 

 erably above the upper anthers of the same flower, and 



* " Ueber den Trimorphisrmis der Pontederien," 'Jenaische Zeit- 

 schrifV &c., Band 6, 1871, p. 74. 



