Chap. IV. PONTEDBEIA. 183 



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. ?] (PONTEDEKIACE^). 



Fritz MiiUer found this aquatic plant, which is al- 

 lied to the Liliacese, 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 conside- 

 rably above the upper anthers of the same flower, and 

 stands on a level with the upper ones of the short-styled 

 form. In the latter the stigma is seated beneath both its 

 own sets of anthers, and is on a level with the anthers 

 of the shorter stamens in the long-styled form. The 

 anthers of the longer stamens of the short-styled form 

 are to those of the shorter stamens of the long-styled 

 form as 100 to 88 in length. The pollen-grains distended 



* "XJeber den Trimorphismus Zeitsohrift,' &c., Band 6, 1871, 

 der Pontederien " ; 'Jenaische p. 74. 



