DISPERSION OF POLLEN BY THE WIND. 131 



shaped leaves aiTan£;ed in fascicles at the ends of the creeping stems which are 

 attached to the inud by root-fibres. In the axils of these leaves a variety of buds 

 are produced — in some cases one only which constitutes the starting-point of a 

 new creeping shoot; in others three close together, one of which grows in length 

 parallel to the bottom and develops a foliage-bud at its extremity, whilst the two 

 others grow straight upward, or there may be two, of which one elongates in a 

 horizontal direction, whilst the axis of the other rises towards the surface of the 

 water. Each of the upward-growing shoots terminates in a kind of bladder 

 composed of two concave and somewhat transparent bracts, one of the pair 

 overlapping the other so as to close the bladder securely. Within these bladders 

 are the flowers. Of the individual plants some develop female flowers only, 

 others male flowers only. The former occur singly in the bladders. Each possesses 

 a long cylindrical inferior ovary crowned by three relatively large stigmas with 

 bi-lobed apices and fringed margins. The stigmas are surrounded by an envelope 

 consisting of an upper whorl of three small abortive petals and a lower whorl 

 of three large ovate-lanceolate sepals. These floral segments are invariably so 

 disposed as to allow the finely-fringed margins of the stigmas to project somewhat 

 beyond the perianth-lobes so that pollen may be caught by the fringes from the 

 side. This is also the reason why the three inner perianth-lobes are stunted, for 

 if they wei-e as large as the outer three the stigma would be covered in at the 

 side and no adhesion of pollen could take place. When the stigmas have reached 

 the stage of being adapted to the reception of pollen, the top of the bladder 

 investing the flower splits ; the ovary elongates, flower and stigma are pushed 

 up above the envelope, and appear on the surface of the water, where they are 

 spread out in the medium of the air (see fig. 227). The phenomenon described 

 is only rendered possible by the fact that the stalk of the pistilliferous flower 

 lengthens to an extraordinary extent, and does not cease growing until the flower 

 it bears has reached the surface of the water (c/. vol. i. p. 667). 



The case of the stamiual flowers is utterly different. They are not solitary, 

 but grow in large numbers in a bunch on an axis which stands up in the middle 

 of the investing bladder. The two leaves composing the bladder become disjoined 

 under water, and expose the raceme of spherical buds. The buds are still in situ 

 on the rachis, which remains quite short, the inflorescence being held at a height 

 of about 5 centimetres above the mud, as is shown in fig. 155, p. 667, vol. i. 



.Shortly afterwards one of the most wonderful processes exhibited by the 

 vegetable world is gradually accomplished. The flower-buds hitherto connected 

 with the axis of the raceme by diminutive stalks become detached, ascend in the 

 water, and float about on the surface. At first they are still closed and globular, 

 but soon afterwards they open. The three concave leaflets (sepals) forming the 

 outer whorl of the perianth, which have up to that time been arched like cowls 

 over the stamens, are thrown back and assume the appearance of three boats 

 connected together at one spot, and the stamens, which were originally three in 

 number, but of which only a pair ai-e now furnished with anthers whilst the third 



