44 COMMON POLYPODY. 



The radicles are brown, and thickly clothed with fibrillee : 

 the caudex is a rhizome, about the size of a goose-quill, and 

 entirely covered with a dense, brown, pilose cuticle, which dries 

 up and peels off after one year's growth, leaving the rhizome 

 smooth ; it is decidedly creeping, making annual advances of 

 considerable extent. The young fronds are thrown out ia May 

 and June, and never issue from the growing point of the rhi- 

 zome, a character which will hereafter occupy the attention of 

 all pteridologists : they arrive at maturity early in September, 

 and retain their fuU vigour until the fronds of the succeeding 

 year make their appearance. The young fronds are generally 

 erect at first, but droop by degrees, and are always pendent 

 when mature. The stipes is green, and nearly equal in length 

 to the frond : the frond is strap-shaped, pinnatifid, and acute 

 at the apex, (fig a, page 41) : the pinnse are nearly linear, and 

 rounded at the apex ; their margins are more or less serrated : 

 the usual size is shown in the detached pinnte, represented by 

 figures b and c, (page 41). The fronds are fertile only, and the 

 clusters of capsules are generally confined to the upper part of 

 each : when without fruit, the imperfection arises from uncon- 

 genial situation, and the j)lant is not to be considered in a per- 

 fectly natural and healthy state. The situation of the veins is 

 shown in the detached pinna, (fig. b) : the lateral veins are al- 

 ternate, and each is divided into four branches, three of which 

 extend nearly to the margin, and are incrassated at their termi- 

 nation ; the fourth is directed forwards, and its termination, 

 which is nearly equidistant from the midvein and the margin, 

 bears a circular cluster of capsules, which is entirely without 

 an involucre. A single lateral vein, its four branches, the at- 

 tachment of the capsules, and the extent of the circular cluster, 

 indicated by a dotted line, are shown at fig. d. (page 41). 



In form of frond the common polypody is tolerably uniform ; 

 it is, however, subject to a few variations, some of which are 



