96 THE WOODS1AS. 



but further south it appears to be half evergreen. 

 Among its common names are oblong Woodsia, hairy 

 Woodsia and hair fern. A living plant of this species is 

 illustrated in the initial design for this chapter. 



The Obtuse Woodsia. 



The obtuse Woodsia ( Woodsia obtusd) is the only com- 

 mon member of the genus in eastern North America. 

 It is to be looked for on shaded ledges and in the loose 

 talus at the base of cliffs and seldom occurs in the ex- 

 posed situations affected by Ilvensis. When it does find 

 itself in the sun, the change is apparent at once since it 

 takes on a yellow-green colour and becomes thicker and 

 more erect. 



In length the blades vary from six to fifteen inches. 

 They are oblong ovate in outline and once pinnate with 

 triangular-ovate, rather distant pinnae. The pinnae are 

 pinnatifid, or pinnate near the base, with oblong, slightly 

 lobed pinnules and segments. Both pinnules and pinnae 

 are quite blunt. This feature is one of the points by 

 which it may be distinguished su- 

 perficially from Cystopteris fra- 

 gifts with which it is very often 

 confused. The stipes are about a 

 third as long as the blades, light 

 in colour and bear scattered 

 brownish scales. Similar scales 



FRU.TING PINNA. "* f Und n the ^^ ^ 



blades are nearly always minutely 

 glandular-hairy and the rootstock is short. 



The sori are round and borne near the edge of the 

 segments on ordinary fronds. Under a lens they are 

 among the most beautiful of their kind. As in all the 



