POLYPODIUM. 
—_— 
frequently taken off and wiped. 
There are other kinds of polygala, 
natives of Europe, which are her- 
baceous perennials; and others 
which are natives of North Amer- 
ica, some of which are annuals and 
some perennials. All the herbace- 
ous Polygalas are hardy dwarf 
plants, very suitable for rockwork ; 
and they may be grown in any 
common soil, though they prefer 
peat or very sandy loam. Some of 
the kinds of Polygala are now in- 
cluded in the genus Muraltia, the 
type of which is P. Heistéria; 
and others in the genus Mundia, 
the type of which is P. spindsa. 
Potyeona\tum.—Smildcee.—So- 
lomon’s' Seal. Hardy perennial 
plants, which require no other care 
than planting in any common gar- 
den soil. They will thrive either 
in exposed situations, or under the 
shade of trees, but the flowers are 
generally largest when the plants 
are grown in the shade. 
Poxty'conum.—Polygonee.—This 
is a very extensive genus, andj 
embraces a great many very dif- 
ferent plants; some of which are 
British weeds, and others stove 
plants from the East Indies or New 
South Wales. Some of the com- 
monest kinds in Britishgardens are 
the Buckwheat (Poly'gonum fago- 
py\rum), the garden Persicaria, (P. 
Persicaria), and the Water-pepper, 
(P. Hydropiper), the beautiful pink 
flowers of which are so ornamental 
in the ponds in Kensington Gardens, 
and other places. Plants so various 
in their nature, require of course 
different kinds of soil and situation ; 
but they will all grow in sandy 
loam, and are generally of the 
easiest culture. 
Potyro\p1um.—Cryptogamia F%i- 
lices.—An extensive genus of very 
beautiful Ferns, some of which are 
natives of Britain, and others are 
exotic. All Ferns should be grown 
330 
and therefore the glasses should be 
POTAMOGETON. 
in shady, damp places; and the 
hardy ones thrive most in a shrub- 
bery under the dip of trees, where 
few other plants will grow. The 
exotic kinds should be grown im a 
stove glazed with green glass; and 
the atmosphere should be kept damp 
by water being frequently poured on 
the floor and flues. 
Pomapbe/rris. — Rhamnacea. — 
Australian shrubs with cymes of 
yellow flowers and generally woolly 
leaves, nearly allied to Ceanothus. 
They are very nearly hardy, and 
may be grown in the open air with 
a little protection during winter. 
They should be grown in sandy peat, 
or in a mixture of peat and loam ; 
and they are propagated by cuttings. 
PoMEGRANATE.—See Pu'nica. 
PonrepE Rria.—Pontederacee. — 
Stove aquatics that should be 
planted in rich loamy soil, and the 
cistern filled up with water. ‘They 
are increased by dividing the roots. 
Popry.—See PApaver. 
Porcupine Cactus.—See Ecut- 
Noca’CTUS. 
Portia'np1A.— Rubidcee.—-Stove 
shrubs, natives of Jamaica, with 
very showy flowers. They should 
be grown in sandy peat or very 
sandy loam. In Jamaica these 
plants grow on calcareous rocks, 
where they form low trees, with 
large and beautiful tube-shaped 
flowers, which are delightfully fra- 
grant. There are but two species 
known, one of which has white 
and the other scarlet flowers, and 
they are both propagated by cut- 
tings in sand, under a bell-glass, 
and plunged into bottom heat. 
PortucaL LaureLt. — Cérasus 
Lusitanica.—A handsome ever- 
green shrub, which thrives best mn 
moist shady situations, and which 
sometimes attains the size of a tree. 
In Ireland, Portugal Laurels attain 
an enormous size, the moisture of 
the climate suiting them admirably. 
Potramoce‘ton. — Alismacee. — 
4 eel Fal 
