15-1 
AQUARIUMS AND AQUATIC PLANTS. 
cordate leaves and white flowers in July : 
native of North America. N. minor, (smaller,) 
has cordate leaves and white flowers in July : 
native of North America. N. nitida, (shining 
cup-flowered,) has cordate leaves and white 
flowers from June to September : native of 
Siberia. N. pygmcea, (pigmy,) flowers from 
May to September, and has cordate leaves and 
white flowers : native of China. The genus 
belongs to the natural order NymphasaceaB. 
Orontium. — Of this genus there are two 
species of little beauty, 0. aquaticum, (aquatic,) 
from North America ; and O. japonicum, 
(Japan,) from Japan. The Indians gather 
the seeds, and eat them when dried, like peas, 
boiling them repeatedly before they are fit for 
use. The latter plant is also called Rohdea 
japonica. They belong to the natural order 
Orontiaceoa. 
Polygonum. — Several of the species are 
aquatic, and they are mostly worth growing, 
either for their flowers or their habit. P. am- 
phibium,, (amphibious,) is a floating peren- 
nial plant, with oblong-lanceolate leaves, and 
spikes of pink flowers : a native plant, found 
in ditches and rivers. P. coccineum, (scarlet,) 
is a pretty perennial, with scarlet flowers, 
from June to August : from North America. 
P. nilotkum, (Nile,) is inconspicuous. P. 
mite, (mild Water pepper,) is a native annual 
plant, bearing red flowers, from June to 
August. P. sahugineum, (briny,) has pretty 
pink flowers, from June to August, and is 
from the Caucasus. P. senegalensis, (Senegal,) 
is from Geneva, and has red flowers. P. liy- 
dropiper, (Water pepper,) is a native plant, 
and has red flowers. The native species 
become rather troublesome weeds in some 
places. They belong to the natural order 
Polygonaceas. 
Pontedera. — There are three hardy Pon- 
tederas. P. ccerulea, (blue-flowered,) is a 
perennial plant, growing erect, about two feet 
high, with cordate-lanceolate leaves, and 
crowded spikes of blue flowers, which are 
produced in August. It is a native of North 
America. P. cor data, (heart-leaved,) has 
heart-shaped leaves, grows two feet high, and 
bears blue flowers from June to August : 
native of North America. P. angustifolia, 
(narrow-leaved,) has long triangular leaves, 
and spikes of blue flowers, produced from 
June to August; it grows two feet high: also 
a native of North America. P. lanceolata, 
(lanceolate,) grows two feet high, and has 
lance-shaped leaves, and blue flowers in Au- 
gust: native of North America. The three 
last require slightj protection. These plants 
belong to the natural order Pontederaceas. 
Potamogeton. (Pond-weed.) — This is a 
family of weedy plants, all natives of lakes, 
rivulets, and ditches in the country. There 
are about a dozen species, many of them pos- 
sessing interesting foliage. They belong to 
the natural order Juncaginaceas. 
Pro&erpinuca palustris, (marsh,) and P. 
pectinata, (pectinated,) are curious small an- 
nuals, with white flowers. They belong to 
the natural order Haloragacese. 
Ranunculus. (Crowfoot.) — There are seve- 
ral hardy perennial species, of more or less 
floating habit. M.aquatilis, (water,) has leaves 
of various kinds ; those submersed are capil- 
lary and multifld, the others three-parted : 
this plant produces numerous white flowers, 
and clothes the pools and ditches, where it 
abounds, with a white mantle during the early 
part of summer : pantothrix, a plant, with 
the leaves all capillary, is a variety. R. hede- 
raceus, (ivy-leaved,) R. tripartitus, (three- 
parted,) and R. obtusiflorus, (blunt-flowered,) 
with some varieties, are all of the same habit, 
and produce white flowers. i2. polyphyUus, 
(many-leaved,) is an interesting annual, bear- 
ing yellow flowers in May and June, and 
growing nearly a foot high : it is a native of 
Hungary. These plants belong to the natural 
order Ranunculaceas. 
Richardia ceth.iopica, (Ethiopian Richar- 
dia,) is a very handsome plant, usually grown 
in a green-house, but hardy enough to endure 
in water out of doors, if kept under water at a 
sufficient depth. It grows about a foot high, 
with erect arrow-shaped leaves, and handsome 
cucullate one-sided spathas, which in green- 
houses are produced usually during the early 
part of the summer. It is a native of the Cape, 
and belongs to the natural order Araceas. 
Rumex. (Dock.) — Though a weedy genus, 
and possessing no beauty in its flowers, there 
are one or two species that are useful for 
producing effect, in collections of water-plants, 
from their bearing fine broad conspicuous 
leaves. jR. Hydrohpathum, (great Water- 
dock,) is a native plant, growing on river 
banks, with lance-shaped leaves, from one to 
two feet long. R. aquations, (grainless Water- 
dock,) has also large leaves of an oblong 
figure, and is a native plant, found in watery 
places. They belong to the natural order 
Polygonacese. 
Sagittaria. (Arrow-head.) — Some of them 
are pretty plants ; they are all perennials. 
S. sagittifolia, (arrow-leaved,) is one of the 
handsomest of British plants ; it grows two 
feet high, with arrow-shaped leaves and white 
flowers, from June to August : there is a 
double-flowered variety : it is found in rivers. 
S. rigida, (rigid,) has lanceolate leaves and 
white flowers in June and July: grows a foot- 
and-a-half high : native of North America. 
S. latifolia, (broad-leaved,) grows a foot high, 
and has arrow-shaped leaves and white flowers 
in July and August : native of North America: 
