POLYPODIUM. 193 



tourists and plant-collectors, they bring home only flowering 

 plants, such as the beautiful blue-flowered Gentian : hence 

 the Ferns of that country are comparatively scarce, and 

 would well repay some future collector if he would bring 

 home a good batch, especially of the beautiful P. alpestre. 

 Fronds lance-shaped, growing a foot high, bipinnate; pinnae 

 or side wings sharp, lance-formed, shortest near the stalk ; the 

 leaflets deeply-cut and oblong in shape. Spore-masses in the 

 middle of the leaflet in one row, and round iu shape. Hoot- 

 stock short and creeping. Increased by division. There is 

 a good plant of this interesting scarce Fern at Kew. It is 

 deciduous that is, dies down or loses its fronds in winter. 



P. CALCAREUM (Limestone Polypody) . Though this delicate 

 Fern is common iu some parts of Britain, it is also widely 

 distributed over Europe, and is even plentiful in North 

 America. The fronds grow 9 inches high, are triangular in 

 form, stand erect, the frond lying almost horizontal, with 

 three branches. Each branch is twice-cut, or doubly pinnate ; 

 pinnae crenated or hollowed. Spore-masses round, placed just 

 within the edges of the leaflets. Veins simple, or rarely forked. 

 Rootstock rough, scaly, creeping very much : hence it is easily 

 increased by division. It is deciduous : therefore the best 

 time to increase it is in spring, just before the new fronds 

 appear. We have found it in great abundance growing near 

 rocks in the neighbourhood of Pately Bridge, in Yorkshire, 

 a locality rich in Ferns. 



P. DEYOPTEEIS (Three-branched Polypody, or Oak Fern). 

 This British Fern is found also plentifully in all four quarters 

 of the globe. There is no hardy Fern more lovely than this : 

 the green is peculiarly beautiful. We can distinguish it at 

 once by its lovely colour. It is also very easy to cultivate ; 

 all that is required is a dry, rather shady situation, with a 

 light soil to run in. Fronds ternate that is, with three 

 branches, broad and deflexed, bipinnate; leaflets distant and 

 partially crenate. Spore -masses somewhat oblong a rare 



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