2 



THE BOOK OF CHOICE FERNS. 



others through its fronds being bipinnate (twice divided to the midrib) and 

 through its stem being of a twining nature. 



The distinctive characters of Blechiwm he in the disposition of the sori 

 (clusters of spore cases), which are hnear (long and narrow), continuous or 

 nearly so, and occupy a position parallel with, and usually contiguous to, the 

 midrib. Their involucre (covering) is membranous and distinct from the edge 

 of the frond. With the exception of B. {Saljnchlcena) volubile, the fronds of 

 which are bipinnate, all the Ferns contained in the genus have their fronds 

 either simple (undivided), as in B. Lanceola ; pinnatitid (the divisions of the 

 frond not extending quite to the rachis, or stalk of its leafy portion), as 

 is the case in the popular A. brasiliense ; or simply pinnate (only once 

 divided to the rachis), hke those of the common B. occidentale and 

 B. orientale. The veins, usually free, are forked ; those of the fertile fronds, 

 which are slightly contracted, being combined near their base at the point 

 of forking by a transverse vein, and forming the sporangiferous receptacle 

 near the midrib. 



Culture. 



This genus is composed of mostly handsome-growing plants, of strong 

 habit, very useful for decorative j)urposes, although there are also included in 

 it several dwarf kinds that are jDarticularly adapted for growing in Fern-cases 

 or in shallow crevices in the rockery. Like the Lomarias, to which they are 

 closely allied, but from which they differ in not producing separate fertile 

 fronds, the Blechnums are mostly hardy, of robust constitution, and of rapid 

 growth. They also have a particular dislike to water over the fronds, which 

 causes them to turn first brown and then black in a very short time, unless 

 the plants are in a very light, warm, and well -ventilated place, which, to 

 a certain extent, counterbalances the effects of the superfluous moisture by not 

 allowing it to remain on the foliage long enough to injure it. Blechnums are 

 not at all fastidious as to their food, and will thrive in almost any compost ; 

 but their fronds become stouter and have more consistency when grown in 

 a mi.xture of two parts peat, one part loam, and one ^ixi-t sand, with good 

 drainage, taking care that the roots never suffer from Avant of water. Propa- 

 gation is usually effected by means of the spores, which are produced in 

 abundance, and which germinate very freely when sown in heat. 



