Keegan: The Wild Cherry. 



219 



long" and strong" roots deeply sunk, with no formation of adven- 

 titious buds, and therefore of stoles or suckers along the lateral 

 roots, such as are observable in some of the allied species. I have 

 never had the opportunity of investigating - the main root or the 

 deeply sunken portions of its structure ; but as respects such 

 parts of the creeping- roots (though I can hardly call them really 

 'roots') as I have examined, the following- notes, however 

 incomplete, may be acceptable. I have been rather surprised 

 to find in these groundling - outgrowths a remarkable develop- 

 ment of the fibres both in the bark and the wood, while the 

 vessels are comparatively sparse, thus reversing- what is usually 

 the ordinary histological constitution of the true roots. Some- 

 times I have found the medullary rays very rich in starch ; at 

 other times, and when the stem wood had abundant starch, the 

 wood of these creeping- org-ans was almost empty of this carbo- 

 hydrate ; phlorogiucin of course is invariably present in copious 

 quantity. The bark, which was free of the tenacious superficial 

 periderm of the stem, or at all events, it is not so well developed 

 there, contains much tannin and its phlobaphene, and a con- 

 siderable quantity of a bitter principle which has none of the 

 characters of phloridzin. The tree is not exacting- as reg-ards 

 the choice of soil, and is frequently seen to prosper -where other 

 species languish ; but it evidently prefers the clayey and moist 

 soils of plains and hills — a bottom where abundant supplies of 

 lime and magnesia are available, and where manganese and iron 

 can be easily absorbed. The wood is subject to a remarkable 

 malady called giumnosis, the symptoms of which are an extra- 

 ordinary formation and accumulation of gum in special reservoirs 

 (lacunae) hollowed out chiefly in the youngest annual layer as 

 the result of the destruction of some of the living cells which 

 compose it. These cells, which may be regarded as a special 

 tissue, are filled with starch, and enlarge, develop, multiply, 

 and thicken with extraordinary energy ; soon the starch is 

 dissolved, the cell-walls disorganise, plates of gum are seen to 

 amass between their successive cellulosic layers, which now 

 Unroll and exfoliate and also eventually dissolve, leaving the 

 lacuna (gum-passage) filled with the gum, which, when it 

 happens to be very abundant, sometimes penetrates the bark 

 and appears on the outer surface thereof as semi-transparent 

 amber globules. In this case the tree is stimulated to produce 

 fresh quantities, with the result that its reserves are soon 

 exhausted and it dies. It is evident in any case that the gum 

 is not the outcome of the normal or healthy activity ot the 



1900 July a. 



