CYSTOPTERIS FRAGILIS. 79 



An indigenous species, deciduous and hardy. It is to be 

 met with in a vast number of places in Great Britain. 



A native of England, Scotland, Ireland, Hebrides, throughout 

 the whole of Europe, India, Persia, Armenia, Siberia, China, 

 California, Mexico, Guatemala, Columbia, Venezuela, West 

 Indies, New Granada, Chili, Port Famine, North Atlantic 

 Islands, Abyssinia, and Tasmania. 



It grows in the fissures of rocks and masonry. 



Introduced into the Poyal Gardens, Kew, in 1798. 



Fronds herbaceous, smooth, sub-bipinnate, (occasionally tri- 

 pinnate,) and oblong-lanceolate in form; pinnse ovate-lanceolate; 

 pinnules ovate near the base, oblong near the apex, and toothed. 



Yeins ilexuose and branched. Fructification covering the 

 under side of the frond. 



Sori numerous and nearly circular. Phizoma perennial, short, 

 tufted, and decumbent. 



Stipes slender, brown, and slightly scaly near the base. 



Length of frond from three to eighteen inches; colour dull 

 green. 



Amongst the varieties Mr. Moore gives — 



1. — FragiUsj var. dentata. Figured here as a distinct 

 species. 



2. — FragiliSi var. angustata. This is much attenuated and 

 lengthened at the apex; it is large in growth, having long 

 narrow teeth on the lobes. 



3. — FragiUs, zar. Dichieana. Small, from four to five inches 

 in length; fronds narrow and bipinnate; pinnules blunt. 



4. — FragiUs, var. ohtusa. Lanceolate; pinnules brief and 

 blunt, deeply pinnatifid. Length of frond from eight to twelve 

 inches. 



5. — FragiUs, var. decurrens. Discovered in Fife, by Mr. A. 

 Tait. More acute than C. Dichieana. 



6. — FragiUs, var. interrupta. Fronds narrow and very dis- 

 similar. 



The wood-cut illustration is a very distinct variety found at 

 Moffat, by Professor Balfour. 



This Fern is subject to the ravages of a parasitical bright 

 yellow fungus, the JJredo JiUctiin; all damaged fronds from 

 this cause should be cut away, as it spreads rapidly over the 

 fronds. 



