LIFE HISTORIES OF FAMILIAR PLANTS 



pocket-like covering at the tips of the frond 

 segments ; in still other genera they are seen as 

 isolated bands on the under surface of the fronds, 

 as in the Hart's-tongue Fern ( Scolopendrium vitl- 

 gare)f or in spots, which may be covered with a 

 protective scale, as in the common Male Fern 

 (Aspidium Filix-7nas), or uncovered as they get 

 older, as in the genus Polystichum (Fig. ii8, Plate 

 84) ; indeed, the variety of their arrangement is 

 almost endless. The Royal Fern (Osmicnda 

 regalis) (or flowering fern, as it is incorrectly 

 called) bears its fructification in clusters on the 

 ends of the fronds, distinct from the leaf- like part ; 

 hence it appears to produce a flowering or fruiting 

 branch. 



It is a common idea that each of the little 

 bodies that constitute these brown clusters is the 

 spore, or seed, from which new ferns are 

 developed; but, although they are so small that 

 they generally need a magnifying lens to reveal 

 their individuahty, yet each one is a little capsule 

 containing some sixty-four spores. In the en- 

 larged figures shown in the illustrations each little 

 capsule, or spore-case, will be seen to be nearly 

 surrounded with a thickened and annulated band. 

 This band, under atmospheric influence, develops 

 a tendency to straighten out as the capsule dries 

 and matures. Eventually it suddenly uncoils, and 

 so ruptures the walls of the spore-case and, by the 

 sudden explosion, the microscopic spores are dis- 

 charged into the atmosphere like a tiny pufF of 

 smoke. 



?94 



