256 
THE FERN WORLD 
grow upon the tops and at the sides of old ruins and old 
walls ; in clefts of rocks ; on the sides of old bridge arches ; 
upon the tops of hedge-hanks ; and in stony and woody 
hollows in the hedge-sides. It is stunted or luxuriant, 
according as the situation it grows in provides more or less 
abundantly the necessary conditions of moisture, shade, and 
leaf-mould. In the hedge-top, where its roots — luxuriating 
in the deposits of leaf-mould upon hollow woody stumps — 
creep under the gnarled and twisted roots of ivy or other 
shrubs, and revel in the dampness and shade occasioned 
by the sheltering vegetation above, the Common Polypody 
becomes a magnificent plant. But when it grows as it 
often does between the little crevices in a stone wall exposed 
to the sun and wind, the plant becomes a pigmy, and its 
fronds barely reach the minimum length usually assigned 
them. 
Description. — The capacity for development exhibited 
by the Common Polypody in Britain is far greater than 
botanical writers have been wont to admit. The maximum 
length of its frond is usually given at from eighteen to 
twenty inches. It is perhaps not often that specimens are 
seen whose fronds exceed this limit. We desire, however, 
to put on record the fact that from the top of a shady 
hedge-bank in a Devonshire lane, we have gathered speci- 
mens, not once only but several times, two feet six inches in 
length. 
The fronds, which are evergreen in sheltered situations, 
grow at right angles from a somewhat thick fleshy rhizoma, 
which branches in various directions, and is provided with 
an abundant mass of fibrous rootlets. The stipes, smooth, 
brittle, aud of a whitish green, is usually about the same 
length as the leafy portion of the frond, but is sometimes 
shorter and sometimes much longer, more especially in the 
larger specimens already referred to. The leafy part is in 
