560 THE FBKN FAMILY. [Polypodium. 



email lobes. Segments thin, light green, obtuse, slightly crenate, quite 

 glabrous. Sori near the margins of the segments. Phegopteris Dryop- 

 teris, Fe"e. 



In rather dry woods, in Europe and temperate Asia, from the Medi- 

 terranean to the Arctic regions, and in North America. Not uncommon 

 in western, central, and northern England and Scotland, rare in North 

 Ireland. Fr. summer and autumn. P. calcareum, Sw. (P. Robertianum, 

 Hoff m. ) is a variety of rather stouter growth, usually with rather less 

 difference in size between the lower pair of pinnules and the succeeding 

 ones, and is covered with a glandular meal. It occurs here and there, 

 in more open rocky situations than the common form, and especially in 

 limestone districts. 



. V. ALLOSORUS. ALLOSORUS. 



Delicate Ferns, with tufted, much divided fronds ; the central ones 

 erect and fruiting ; the outer ones barren, with broader segments. Sori 

 circular, but so close as to form compact lines along the margins, 

 covered over when young by the thin edge of the frond itself. 



A small genus, confined to the mountainous or northern districts of 

 the northern hemisphere. 



1. A. crispus, Bernh. (fig. 1285). Rock Bracken, Parsley Fern. 

 Stock densely tufted with brown scarious scales. Fronds 2 or 3 times 

 pinnate, ovate or oblong in their general outline, on slender stalks almost 

 without scarious scales ; the outer barren ones about 5 or 6 inches high, 

 somewhat resembling Parsley-leaves, with numerous small, obovate or 

 wedge-shaped and deeply-toothed segments. Fruiting fronds f to 1 foot 

 high, with equally numerous oblong or linear segments, the thin mem- 

 branous edges turned down over the son. Cryptogramme crispa, Br. 



In the mountains of Europe, from the Pyrenees and Apennines to the 

 Arctic regions, usually local, but often very abundant in particular spots. 

 In Britain, chiefly in Scotland and northern England, but occurs also in 

 central and western England ; very rare in Ireland. Fr. summer. 



VI. GEAMMITIS. GRAMMITIS. 



Fronds much divided. Sori linear or oblong, simple or forked, not 

 marginal, and without any indusium. 



A considerable genus, chiefly tropical, including many of those elegant 

 Ferns often seen in our hothouses, with a golden or silvery dust on the 

 under side of the fronds. The generic name Grammitis, Swartz, has 

 the right of priority over that of Gymnogramma, Desv. 



1. G. leptophylla, Swartz (fig. 1286). Small G.A delicate little 

 Fern, resembling at first sight very small specimens of Allosorus crispus. 

 Fronds in little tufts, although the whole plant is usually annual ; the 

 outer fronds short, with few broadly obovate or fan- shaped segments, 

 often barren ; the others erect, 2 to 6 inches high, with slender black 

 stalks, twice pinnate, with numerous small, thin, obovate, deeply- 

 toothed or lobed segments. Sori oblong, at length nearly covering the 

 under surface of the segments. Gymnogramma leptophylla, Desv. 



