122 NEW ZEALAND PLANTS. 
In certain Auckland swamps there are various rush-like plants— 
e.g., the great spike-rush (Elaeocharis sphacelata), 2 to 3 feet high, 
distinguished by its stout cylindrical hollow green stems, which 
are divided by partitions; the common twig-rush (Cladium tereto- 
folium) ; the jomted twig-rush (C. articulatum), taller (up to 6 feet) 
than either of the preceding, and growing on rather drier ground, 
where it forms pure colonies of cylindrical stout stems divided by 
transverse partitions and produces a brown drooping inflorescence 
a foot long. There will also be a good deal of the cyperus sedge 
(Carex pseudo-cyperus var. fascicularis), and the creeping New 
Zealand burr-reed (Sparganium subglobosum), with its long bright- 
green almost three-edged leaves, and its flowers, some male, some 
female, crowded into rounded heads. The rather rare swamp- 
fern (Dryopteris Thelypteris var. squamulosa) may be occasionally 
met with, but the most common fern of swamps is the long hard- 
fern (Blechnum capense). 
South Island swamp contains fewer species than that of the 
North Island, but it has a few plants of its own, such as the swamp- 
broom (Carmichaelia paludosa) (Westland), a divaricating species 
of the same genus, also occurring in Westland (probably C. grandi- 
flora var. divaricata), and the rare climbing-broom (C. gracilis), a 
scrambling liane. In Stewart Island the coastal jointed rush (Lepto- 
carpus simplex) occurs in fresh-water swamp. So, too, has this plant 
ventured farther inland, or been left behind at some period of its 
wanderings, on the gravel shores of Lakes Manapouri and Te Anau. 
The bog-moss (species of Sphagnum) is the most characteristic 
plant of bogs. It forms great rounded soft cushions and hillocks of 
a whitish colour, into which one sinks when walking upon them, 
and on which many of the bog-plants make their home. Taking 
the whole New Zealand region, there are about 18 species of 
Sphagnum, some of which are also Australian. 
Sphagnum possesses some characteristics which must be noted 
here. The outer part of its long stem consists of an external layer 
of large clear thin-walled cells, lacking leaf-green, but with their 
walls stiffened by thickenings, and communicating with one another 
and with the outer world by means of large holes in their walls. 
Cells similarly constructed are also present in the leaves, but there 
they are surrounded by a network of very narrow cells containing 
leaf-green whose colour is masked by the colourless cells. Water is 
