,34 



BRITISH FERNS. 



here it seems necessary to add that this, or something closely ap- 

 proaching it, is the Polypodium rhaeticum of Dickson, Withering, 

 and Bolton, the Polypodium rhasticum of Linneus being nothing 

 more than a frond of Polypodium Filix-femina of the same author. 

 Cystea angustata, Smith. Rhizoma tufted, or somewhat creep- 

 ing (!), black, with long fibres and rusty scales. Fronds several, 

 erect, twelve or fifteen inches high, of which the slender 

 blackish, smooth, and naked rachis occupies 

 more than a third, sometimes nearly half; 

 the midrib is still more slender, and, like 

 every other part, quite smooth, without any 

 membranous border. Pinnae bright green, 

 from twelve to fifteen pair, of a moderate 

 length, nearly opposite, and taper-pointed; 

 the lowermost rather shorter and more re- 

 mote from the next than those about the 

 middle of each frond ; all pinnate, with a 

 scarcely bordered midrib. Pinnulae about 

 ten on each side, alternate, lanceolate, de- 

 current, rather bluntly pointed, sometimes 

 tapering to the extremity ; all either deeply 

 pinnatifid, with acute, oblong, wavy seg- 

 ments ; or, in less luxuriant plants, slightly 

 pinnatifid, or only wavy at the margin ; the 

 ribs of all more or less wavy. The ultimate 

 divisions, in every instance, are oblong or 

 linear, never dilated, rounded, or ovate ; they 

 are sometimes, though seldom, notched or 

 cloven at the end. By this linear or oblong 

 mode of division, and its thinner more pliant 

 texture, the present may readily be known 

 from the preceding, with which it has gene- 

 rally been confounded. The masses, much 

 smaller and less prominent than in those 

 species, always continue distinct, standing 

 either solitary or in pairs, towards the bottom of each lobe or 

 tooth, and are round, at first pale, and subsequently brown. 

 Eng. Flora, iv. 502. 



The frond to which Sir J. E. Smith refers as having been 

 found at Gordale, in Craven, still remains in his Herbarium, and 

 is figured above. 



