86 WHERE TO FIND FERNS. 



XIX. THE THREE-BRANCHED POLYPODY. 



Polypodiinn dryoptcris. 

 (Plate IX., Fig. 3, page 65.) 



LENGTH OF FROND. Six to twelve inches. 



GENERAL DESCRIPTION. Roots fibrous, delicate, nu- 

 merous. Rootstock, a slender, somewhat black rhizoma, 

 which creeps extensively, in a horizontal direction, upon 

 or just underneath the soil. Fronds triangular, abundant, 

 springing from numerous points of the rhizomas, delicate, 

 brittle, golden green, herbaceous, each with a slender, 

 brittle, pale-green stipes and a three-branched leafy part, 

 about half the length of the stipes ; rachis and rachides 

 also very slender, delicate, and brittle. The branches of 

 the frond grow at right angles to each other, and each is, 

 itself, more or less triangular in shape, with a clear space of 

 stem between it and the point of attachment to the rachis. 

 The two lower branches are ordinarily pinnate at and near 

 the base and pinnatifid higher up, and are divided into 

 pairs of oblong, more or less deeply-indented pinnules, 

 the lower ones (near the main rachis) of each pair being 

 longer than the upper cnes. The upper branch is 

 divided into opposite pairs of more or less deeply-cleft 

 pinnae, which become gradually merged into each other 

 towards the apex of the branch that forms the apex of 

 the frond. Fructification produced in rows of non- 

 indusiate sori, one row on each side of the midvein of 

 pinnule or pinna, according to the size and development 

 of the plant. 



HABITATS. Slightly less moist than those of Polypo- 

 dium phegopteris : shady woods amongst underwood and 

 in rocky crevices ; streamsides and shady hedgebanks in 

 hilly, moorland, or mountainous districts. 



