ALGJ3, OB SEA-WEEDS. 



147 



popularly applied. The most common, and at the same time the least noticeable, 

 forms are the minute substances which appear in and upon decomposing fluids, and as 

 vegetable parasites upon many living plants and animals (Fig. 300). All alike, how- 

 ever, consist exclusively of cellular tissue, but differ greatly'in its arrangement, and 

 especially in the nature of their reproductive organs. In the minute bodies just 



Fig. 300. 



Fig. 301. 



Fig. 300. The conformation of the common Mushroom (Agaricus campestris). A. a, the pilous ; 

 b, the lamella, covered by the hymenium ; c, the stripe ; d, the mycelium. B. a portion of the 

 hymenium, with basidia in four different stages of formation. C. a perfectly developed spore 

 in one of the processes of the upper part of a basidium. 



Fig. 301. Mucor Mucedo, showing the asci, A, and the sporidiae, B. 



mentioned, the organ of fructification is simply one enlarged cell, containing the 

 gporules or spores ; but in the common Mushroom there are true sporidia contained in 

 asci or sporule cases, and in a few there are moveable spiral fibres or elaters. The 

 former division of fungi is the most interesting and accessible ; so that we would urge 

 our readers, possessed of some microscopic knowledge, to examine the various forms of 

 mould so universally distributed. No preparation or subdivision of the substance is 

 necessary, except that of placing a very small portion of it in a little water. 



Algae, or Sea-weeds. This is the last one of the Fungi, the lowest forms of 

 vegetable life and growth, and is the boundary line of, or rather the neutral territory 

 between, the animal and vegetable kingdoms. The members of this class are univer- 

 sally distributed, and are all different, from the string of cells found in a drop of 

 stagnant water to the beautifully varied and large sea-weeds familiar to many of 

 our readers (Fig. 297). It is a class, however, which is best represented in the 

 southern or tropical seas; for there, not only is there greater variety of appearance, but 

 the masses in which they abound almost exceed belief. Moreover, in such, as also in 

 many representations on our own shore, it seems almost impossible to deny the animal 

 characters with which many observers have invested them. Nothing can so much 

 relieve the monotony of a sea-side residence as to fix a microscope on the sands, and 

 examine these beautiful objects, fresh from the salt water. 



As in other families, the reproductive parts, for the most part, are called spores, and 

 are found in the ordinary cells of the plant, as in Fig. 297, or are gathered together 

 into sporangia, or spore-cases, of various kinds. "We cannot enter into the dispute as 

 to the sexuality of these as of other members of the class of flowerless plants, but 



