FIMOES. 627 



In rather dry woods, in Europe and Russian Asia, from the Mediterranean 

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

 central, and nortliern England and Scotland, and occurs also in Ireland. 

 Fr. summer and auiumn. The limestone Polypody (P. calcareum, Eng. 

 Bot. t. 1525, P. Rohertianum, Bab. Man.) appears to be a mere variety of 

 the Oak P., of rather stouter growth, usually with rather less difference in 

 size between the lower pan' of pinnules and the succeeding ones, and has a 

 minute, scaly, or glandular meal on the frond-stalk and principal veins. 

 It occurs here and there, in more open rocky situations than the common 

 form, and especially in limestone districts. 



V. AZiLiOSORUS. 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 fi'ond itself. 



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

 northern hemisphere. 



1. Curled AUosorus. Allosorus crispus, Bernh. 

 {Pteris, Eng. Bot. t. 1160, Cryptogrcmima, Brit. Fl. Rode Brakes, 

 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 Hnear segments, the thin mQmbranous 

 edges turned down over the sori. 



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 and in Ireland. Fr. summer. 



VI. GVMNOGRAIMZ. GYMNOQRAMMA. 



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

 ginal, 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. 



1. Small Gymnogram. Gymnogramiua leptopbylla, Desv. 



A delicate httle Fern, resembling at first sight very small specimens of tlie 

 curled Allosorus. Fronds in little tufts, although the whole plant is usually 

 annual ; tlie 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. 



