THE FLOATING WATER-FERN. 1S) 
CHAPTER VIII. 
PLANT-COMMUNITIES AND PLANTS OF INLAND WATERS, 
SWAMPS, AND BOGS. 
General remarks—The water-ferns—Azolla rubra—The pond-weeds—The water- 
milfoil—Changes in swamp wrought by man—Fresh-water algae—Algae of 
hot-water springs—Definition of term ‘swamp ’’—Species and growth-forms 
of swamp — Conditions for plant-life in swamp— The root of Phormiwm 
tenax—Breathing-roots of the pukatea—Relations of swamp to other plant- 
formations—Vegetation of swamps—Swamp of Auckland—Special South 
Island swamp-plants — Bogs—Sphagnum moss and its peculiarities — 
Dryness of sphagnum-cushions — Origin and distribution of bogs — Life- 
conditions for bog-plants —Growth-forms of bog-plants— The species 
growing in bogs— Some bog associations —Sundews and bladderworts — 
The species of Gunnera — The false snow-grass (Schoenus pauciflorus ) 
plant-association. 
Ir has already been shown that in her forests, grasslands, herb- 
fields, shore vegetation, shrubberies, and on even her frowning cliffs 
New Zealand possesses plants which do not yield in beauty or interest 
to those of any other land. With her seaweeds, too, she is well 
able to hold her own. But when it comes to her fresh-water plants 
she must take a lower place. Rivers, lakes, and smaller sheets of 
water there are in plenty which offer first-class inducements for 
occupation by aquatic plants, but none of the more beautiful kinds, 
except since the advent of the European, have accepted the offer ; 
in vain do we look for indigenous water-lilies like those of the neigh- 
bouring island-continent. Still, for all that, New Zealand’s inland 
waters are not without plant-life, some of which, from the biological 
standpoint, is interesting enough. 
Take the case of the floating water-fern (Azolla rubra). The 
red masses of this curious plant, covering still pools so thickly that 
one might think them dry land, must be known to all. The appa- 
rently upper surface of the upper leaf-lobe is covered with minute 
excrescences, so that it cannot be wetted, and, in consequence, drops 
of water frequently begem the floating mass and glitter in the sun- 
