OHARA. 315 



The fruits, or sori, of Ferns afford a very beautiful 

 variety of objects for the microscopist, and tliey possess an 

 advantage in requiring little or no preparation — nothing 

 more being necessary than that of taking a portion of a 

 frond, place it on a glass-slip under the microscope, and 

 throwing a condensed light ujDon it by the aid of the side 

 reflector. Even germination may be watched by simply 

 employing gentle heat and moisture. Take, as Hofi- 

 meister directs, a frond of a Fern whose fructification is 

 mature, lay it upon a piece of glass covered with hue 

 paper, and place the spore-bearing surface downwards 

 upon this ; in the course of a day or two this paper will 

 be found to be covered with a fine brownish dust, which 

 consists of the liberated spores. These must be carefully 

 collected, and spread out upon the surface of a smooth 

 fragment of porous sandstone, and then' placed in a saucer, 

 the bottom of which is before covered with v/ater ; a glass 

 tumbler being inverted over it to ensure the requisite supply 

 of moisture, and prevent rapid evaporization. Some of the 

 protliallia soon germinate; if the cup be kejDt only slightly 

 moist for some time, and then suddenly watered, a large 

 number of antheridia and archegonia quickly open, and in a 

 few hours the surface of the larger prothallia will be covered 

 with moving antherozoids. It sections of these be made, 

 that is, the canals laid open, with a power of 200 or 300 

 diameters we may occasionally see antherozoids in motion, 



CharacejE. — Ghai^a vulgaris is the plant in whicli the 

 important fact of vegetable circulation was discovered ; 

 Fig. 170, ISTo. 1, is a portion of the plant of the natural 

 size. Every knot or joint may produce roots ; but it is 

 somewhat remarkable, that they always proceed from the 

 upper surface of the knot, and then turn downwards ; so 

 that it is not peculiar that the first roots also should rise 

 upwards with the plant, come out of the base of the 

 branch, and then turn downwards. 



Mr. Yarley noticed : — " The ripe globules spontaneously 

 open; the filaments expand and separate into clusters." 

 " These tube-like filaments are divided into numerous 

 compartments, in which are produced the most extra- 

 ordinary objects ever observed of vegetable origin, Fig. 

 170 A. At first they are seen agitating and moving in their 



