Polypodium hydriforme Ussow is a fresh-water form parasitic on the eggs of the sterlet.
Ussow, " A new Form of Fresh-water Coelenterate " (Polypodium), Ann.
POLYPODIUM, in botany, a large genus of true ferns (q.v.), widely distributed throughout the world, but specially developed in the tropics.
- Polypodium vulgare, of leaf of Polypodium bearing common polypody (about a nat.
These conditions of orchid-growing have undergone great changes of late years, and the plants are grown much as other stove and greenhouse plants in ordinary pots with composts not only of peat but of leaf-mould, and fibres from osmunda and polypodium ferns.