366 Field, Forest, and Wayside Flowers 



neath their bark a store of nourishment which will 

 feed the tender foliage of spring when it first be- 

 gins to grow. 



The leaves now fading have not been suddenly 

 slain by ruthless frost. For weeks they have been 

 bringing to a peaceful and fitting close a life which 

 reached its fulness in the dog-days. While as yet 

 summer was at high tide nature began to form 

 across each leaf-stalk, just at the point where it 

 joined the main stem, a very thin layer of cork. 

 The manufacture of cork is not a trust in posses- 

 sion of the Spanish branch of the oak family. 

 Cork is a constituent in the bark of most native 

 flowering-shrubs and trees. It is also used by vege- 

 tation in repairing its rents and healing its wounds, 

 and sometimes a layer of it is interposed to isolate 

 diseased or dying tissues and, as it were, quarantine 

 them from healthy and growing ones. The 

 " wound-cork " which the trees use in lieu of court- 

 plaster may be covered by the subsequent growth 

 of trunk or branch, so that eventually it lies deep 

 in the woody tissues. 



But wherever it is met with cork can be read- 

 ily recognized under the microscope by the forms 

 of the cells composing it. They are square or 

 brick-shaped, with clear-cut angles, and they lie as 



