568 THE FEKN FAMILY. [Blechnum. 



A small genus, spread over many parts of the world, but chiefly 

 tropical. 



1. B. Spicant, Eoth. (fig. 1307). Blechnum. — Fronds simply pinnate, 

 tufted, of two kinds, the outer barren ones spreading, usually 6 inches 

 to near a foot long ; the segments lanceolate, curved, entire, attached 

 by their broad base ; those in the centre of the frond 1 to 1£ inches 

 long, gradually decreasing towards each end. Fruiting fronds in the 

 centre of the tuft, erect, 1 to 1 \ feet high ; the segments of the same 

 length as in the barren ones, but all narrow-linear ; the under side entirely 

 occupied by the 2 linear sori. B. boreale, Sw. Lomaria spicant, Desv. 



In woods, and rather moist stony places and heaths, generally dis- 

 tributed over Europe, extending from the Mediterranean far into 

 Scandinavia, and occurs in north-east Asia and north-west America. 

 Common in Britain. Ft, summer, rather late, and autumn. 



XII. PTERIS. PTERIS. 



Fronds usually stiff, often large, lobed, or pinnately divided. Veins 

 of the segments branching from the midrib. Sori linear, close along 

 the margin of the frond, with an indusium attached along its outer 

 edge to the margin of the frond, and opening on the inner side. 



A large genus, widely distributed over the globe, and if not very 

 natural, at any rate easily recognised. 



1. P. aquilina, Linn. (fig. 1308). Bracken. — A tall, erect, stiff Fern, 

 with a thick, hard, creeping rootstock. Fronds 1 to 2 feet high in poor 

 soils, 8 to 10 feet high when luxuriant, twice or thrice pinnate; the 

 primary pinnas in pairs at some distance from each other ; the lowest 

 pair much larger, the others decreasing in size and successively developed, 

 giving the whole frond, especially when young or small, a broadly tri- 

 angular outline. Secondary pinnas numerous, linear-lanceolate, deeply 

 pinnatifid or pinnate, always ending in an undivided, crenate, blunt 

 point. Segments ovate or oblong, obtuse and entire, attached by their 

 broad base of a firm consistence, glabrous above, often hairy underneath. 

 Sori in continuous lines along the margins of the upper segments and 

 summits of the secondary pinnas. 



In woods and thickets, on heaths and waste places, dry or moist, but 

 not swampy, in almost every part of the globe, except the extreme 

 north and south. Very abundant in Britain. Fr. autumn. 



XIII. ADIANTUM. MAIDENHAIR 



Fronds usually delicate and divided, the segments more or less wedge- 

 shaped, with diverging forked veins, usually without a midrib. Sori 

 oblong or linear, transverse, at the ends of the lobes on the under side, 

 with an indusium formed from the edge of the frond, and opening in- 

 wards. 



A considerable and well-marked genus, chiefly tropical. 



1. A. Oapillus- Veneris, Linn. (fig. 1309). Maidenhair. — A very 

 delicate tufted Fern. Fronds '6 inches to near a foot long, twice or 

 thrice pinnate, usually broadly ovate in general outline, their slender 



