MICROSCOPIC OBJECTS. 2 



Fig. 3. Spores of the Mushroom (Agaricus campestris), 



x200. 



This drawing illustrates the spores, as they are called, of 

 the common Mushroom, drawn immediately after they were 

 shed by the mature plant. Spores agree so far with seeds, 

 that they reproduce the plant. In their natural growth on the 

 gills they are called basidiospores ; these are common to 

 both the Hymenomycetous and Gasteromycetous Fungi. In 

 the Hymenomycetous, of which the Mushroom is an example, 

 they are produced on the surface of the gills (hymenium) , and 

 generally at the four extremities of a branched cell. The 

 spores are at first nearly colourless, but afterwards gradually 

 acquire a brownish tint. In some species of Fungi they 

 remain white. 



The spores are from -^^ to ^oVo inch in length, and from 

 -^1^- to 4 J^. in breadth. They are best viewed when mounted 

 in liquid. 



Fig. 4. Frond of a Confervoid Alga (Chlorococcum 

 vulgare), x 200. 



This drawing illustrates the green dust or powdery layer 

 (Chlorococcum vulgare) so commonly found on old palings, 

 trunks of trees, &c. The minute seed-like bodies, mostly 

 arranged in groups of fours, of which this substance consists, 

 keep on increasing by cell-division; at least, according to 

 our present knowledge, they have not been proved to arrive 

 at a higher state of being in this respect differing from the 

 spores or seed-like bodies of the Mushroom. It is thought 

 by some scientific observers that it is only a lower form of 

 some lichen ; but the present state of knowledge upon this 

 point is rather uncertain. 



The diameter of the groups of spore-like bodies is from ^-^ 



to wVo incn - 



They may be mounted either in the dry state, in balsam, 



or in liquid. 



