HYDROPHYTES 331 
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 PRIAANS 
contrast is striking (Fig. 303). Fic. 303—Submerged and aerial 
1d. Reed eyanips, <The eS ee poner 
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 nearly 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. 
