HYDROPHYTES 381 



the mucky bottom; and even when they do not send leaves 

 up to the surface of the water, they usually send up the 

 flowers that they may open in 

 the air. In parks and green- 

 houses, the great water-lily of 

 the Amazon (Victoria regia), 

 the largest of all the water- 

 lilies, is commonly seen (Fig. 

 302). Floating and submerged 

 leaves are very different in 

 form, and when both kinds 

 occur on the same plant the 



Contrast is Striking (Fig. 303). FIG. 303. Submerged and aerial 



194. Reed swamps. - The 5KfcU^JL,* P ^*~ 

 reed - swamp plants are tall, 



wand-like forms that grow in the shallow margins of small 

 lakes and ponds (Fig. 304). Prominent among them are 

 cat-tails, bulrushes, and wild rice; and associated with these 

 tall forms the arrowleaf is often found. This assemblage 

 of plants forms the usual high fringe along swampy shores, 

 and they have been called the pioneers of land vegeta- 

 tion ; for their growth and the entangled detritus make the 

 water more and more shallow, until finally the reed plants 

 are compelled to migrate into deeper water. In this way 

 small-lakes and ponds may become converted first into 

 ordinary swamps, and finally into wet meadows. Instances 

 of neaily reclaimed ponds may be found, where bulrushes, 

 cat-tails, and reed grasses still occupy certain wet spots, 

 but are shut off from further migration. 



195. Swamps. Ordinary swamps are occupied by sedges 

 and coarse grasses, giving them a meadow-like appearance. 

 Such swamps often border reed swamps on the land side, 

 and encroach upon them as the reed plants build up land. 

 With the sedges and grasses numerous other swamp-loving 

 plants are found. 



