BRITISH FERNS. 



35 



The fourth and last variety noticed by Smith, and one which 

 Professor Don considers distinct as a species, is called Cystea 

 regia by Smith, who supposes it to be the Polypodium regium 

 of Linneus. (I have carefully examined the specimens preserved 

 under this name in the Linnean Herbarium ; these are three in 

 number: the first appears to be the normal form of fragilis, 

 although the specimen is injured ; the second is the species 

 known by our cultivators as Asplenium fontanum, and the third 

 is the Polypodium dentatum of Dickson.) The only habitat of 

 this plant is a wall at Low Layton in Essex ; the plant received 

 by Smith from Snowdon being very different in appearance, 

 although by that author labelled and even described as identical. 

 Whether this plant emanates from seeds of fragilis or regia is 

 of little moment ; it must have escaped from a cultivated speci- 

 men, and therefore cannot be considered as in a native habitat. 



Cystea regia, Srnith. Rhizoma tufted, scaly. Fronds several, 

 from three to ten or twelve inches high, bright green, lanceolate, 

 twice pinnate, pinnatifid, and finely cut, of a most elegant 

 appearance, quite smooth in every part except a 

 few membranous, torn, pointed, brown scales 

 at the very bottom of the stalk, which is less 

 brittle and juicy than that of C. fragilis. Pinnse 

 and pinnules more generally alternate than oppo- 

 site ; the former with a narrowly-winged or 

 bordered midrib ; the latter ovate, obtuse, 

 deeply pinnatifid, with elliptic, oblong, obtuse, 

 partly cloven, or notched segments, but not 

 elongated, linear, or wavy at the margin like 

 C. angustata ; neither are the ribs zigzag as in 

 that species. Masses of thecas very copious, 

 but small, pale, and scattered, not crowded, nor 

 do they even appear to become confluent. In 

 a young state each is wrapped up in a white 

 membranous concave cover, terminating in a 

 tapering, more or less jagged, point, nearly 1 

 agreeing with C. fragilis ; but the masses are 

 much smaller, and the thecae of a pale brown, 

 never black. Eng. Flora, iv. 303. 



A sketch of a frond gathered from the wall at Low Layton 

 accompanies the description. 



Having now pointed out the characters by which these four 



