ORDER MUSCI. 269 



(c) BLECHNUM, capsules in uninterrupted lines running parallel 

 to the midrib of the frond on both sides ; (d) PTBRIS or brake? 

 capsules forming lines on the edge of the leaf. 



Some ferns bear their fruit in a peculiar appendage, as a 

 spike or protuberance in the axils, or at the base of the leaves ; 

 no appearance of flowers is ever presented. When the brown 

 or white dust-like spots are examined with a microscope, they 

 are found to consist of clusters of very small capsules, at first 

 entire, but afterwards bursting elastically and irregularly. 

 Besides attention to the situation and form of the capsules, it is 

 necessary to observe the membrane which envelopes them ; 

 this is called their involucrum. The seed is as minute as the 

 finest powder, and so light as to be wafted by the air to any 

 distance or height ; we thus often see ferns growing high on 

 the trunks of trees, or on the summits of old buildings. Some 

 ferns grow to a great height in southern latitudes, almost like 

 trees. At the southern extremity of Van Diemen's Land, a 

 species has been found, whose trunks attained to the height of 

 twelve or sixteen feet. One species in our country, ONOCLEA 

 sensibiiis, called the sensitive fern, is said to wither on being 

 touched by the human hand, though the touch of other sub- 

 stances does not produce any similar appearances. 



The number of species of ferns which are already known, 

 amounts to about seven hundred. They generally abound in 

 moist and shady situations, but are sometimes found on rocks 

 and dry places and on the trunks and branches of old trees. 

 The frond or leaf of the fern is often pinnate, or divided like a 

 feather ; sometimes it is undivided and resembles a palm-leaf. 



The EQUISETUM hyemale is known to housekeepers under 

 the name of scouring rushes. The quantity 'of silex contained 

 in the cuticle renders it a good substitute for scouring sand. 



Musci, or MOSSES. 



The 2nd order contains the mosses, which are little herbs 

 with distinct leaves, and often a distinct stem ; their conical, 

 membranous corolla is called a calyptra or veil, its summit 

 being the stigma ; this veil clothes the capsules, which, before 

 the seed ripens, is elevated on a fruit stalk. The capsule is 

 of one cell, and one valve, opening by a vertical lid ; the seeds 

 are very numerous and minute. In some genera the veil is 

 wanting, which serves as a distinction in the order. The bar- 

 ren flower of mosses consists of a number of nearly cylindrical, 

 almost sessile anthers ; the fertile flowers of one pistil, seldom 

 more, accompanied by several barren pistils. Both stamens 



Sensitive fern Number of species-AVhere they generally 

 ing rushes Mosses. 



33* 



