20 MOUNTAIN SHIELD FERN. 



This rare fern seems to have been very familiar to 

 older botanists and herbalists, and is frequently men- 

 tioned by Ray, Gerarde, and others. It is exceedingly 

 difficult of culture, and even when established, is often 

 disappointing to the cultivator; for it is only seen in 

 perfection on its native rocks, in the open air in Ire- 

 land, Scotland, or Wales. In the south of England 

 it seldom thrives, and, on this account, is best left 

 out ot a growing collection of ferns. 



MOUNTAIN SHIELD FERN. 



ASP I DI UN OREOPTERIS. 



[Swartz, Smith, Hooker.] 

 (Fig. 5.) 



SYNONYMS. 



LASTREA OREOPTERIS. Presl, Balnngton (Sweet Moun- 

 tain Fern). 



LASTREA MONTANA. Newman. 

 POLYPODIUM FRAGRANS. Linnceus. 



THIS is a difficult fern to distinguish from Aspi- 

 dium Filix Mas, especially when fully grown. Its 

 fronds are lance-shaped. The pinnules dwindle at 

 the base to a mere leafy excrescence close to the 

 ground. The sori are placed like beads under the 

 edges of the lobes, which do not turn back as in 



