DECOMPOSITION OF PLANTS. 119 



is not quite obvious ; but of that insidious race the 

 byssi, of which family is the dry-rot (byssus sep- 

 tica), the radicles penetrate like the finest hairs into 

 the substance, and thus destroy the cohesion of the 

 fibres. So do the nidulariae, many of the agarics, 

 the boleti, and others ; and it is not unlikely that 

 this operation is the general principle of action of 

 the whole race, though not so obvious in the 

 minuter kinds. These terminators, many of which 

 present but little character to the naked eye, under 

 the microscope we find to be of various forms, 

 though not always so distinguishable from each 

 other as the flowers of our garden. Some of the 

 genera of plants appear to have distinct agents 

 assigned to them^ and the detection and enumera- 

 tion of them have been carried to considerable 

 extent by some of the foreign naturalists ; but, to 

 point out the variety and curious organization of 

 these substances, we will only instance four, to 

 be found on the common plants of the garden or 

 the copse : the laurel, the elm, the sycamore, and 

 the beech. 



The laurel (jprunus laurocerasus) is not, pro- 

 perly speaking, a deciduous plant, though it casts 

 its leaves in considerable numbers during the 

 spring and summer seasons. These long resist the 

 common agents of dissolution, like those of the 

 holly, by means of the impenetrable varnish that is 

 spread' over them. This, however, wears off, and 

 they decay ; but their destruction is at times acce- 

 lerated by a small excrescent substance^ which 



