168 CAUSES OF BARRENNESS, &C. 



of gradual development ; sometimes, in the case of 

 trees, the two principles of growth and fruitfulness 

 progress together, equally balancing each other ; at 

 other times controlling or neutralising each other; 

 abundant fertility checking the growth, and exuberant 

 growth preventing fruitfulness. 



Here it is necessary to observe, that trees may be 

 barren from other causes than over-luxuriant growth. 

 The fructiferous gems or principles may be present 

 though abortive ; trees may be covered with flowers, 

 and yet produce no fruit. This arises either from 

 constitutional weakness, the depredations of insects, 

 or ungenial weather. A vine may show its incipient 

 bunches at every bud that bursts ; but if there be a 

 want of air, or light, or heat, or of sufficient energy 

 in the tree, no flowers will be expanded, nor fruit 

 perfected ; the bunches will be resolved into tendrils. 



When the growth of a tree is moderate, and when 

 flower buds are exhibited over all the spray, not only 

 are the flowers of this year strongly formed and 

 expanded, but those of the next are ready to start 

 forth; and, it not unfrequently happens, do come 

 forth late in the summer or autumn, especially if the 

 first flowers have been cut off by frost, insects, or 

 other accident. It is in such cases we sometimes 

 witness a struggle between the growing and fruc- 

 tiferous principles; some of the second flowers become 

 monstrous; the axis of the shoot being prolonged 

 through and beyond the imperfect flower, leaving a 

 portion of the pulpy part of the pericarpium on the 



