148 HISTORY OF BRITISH FERNS.
of these seems to have the precedence on the ground of
priority, but it has not as yet been adopted in this country.
P o l y po d ium D r yo pt e r is , Linnoeus.— The Tender Tliree-
branched Polypody, sometimes called the Oak Pern. (Plate
II. fig. 1.)
This is at once known among the Polypodies by having
its quite smooth fronds divided into tliree branches; and
when the fronds are but partially developed this latter characteristic
is available, for the three branches are rolled up
separately, and the fronds in the stage alluded to resemble
three little balls set on short slender wires, and supported
by one which is longer and stouter. It is, however, altogether
a slender and delicate plant, its height being commonly
not more than six inches, often less, and sometimes
more, its colour a pale bright green, and its texture fragile.
Hence it is at once destroyed by frost, and soon becomes
rusty and withered by exposure to heat and drought. When
growing in a cool, shady situation, however, it continúes
fresh and cheerful-lookirig from April, when it usually starts
into growth, onwards until it is affected by autumnal cold.
In pots, in Wardian cases, or on sheltered, shady rock-work,
it is alike desirable for cultivation.
The fronds of this delicate little Pern grow from a slender
Piateli,
et l i t l i.
Aeeve ài'Nichols iirvp