VEGETATIVE SPORTS AND FLORAL FKEAKS. 



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pretation apparently is that the terminal bud received some check so 

 that the internodes between the scattered leaves were so reduced as to 

 compel the branches to grow out horizontally ; then, as a consequence of 

 this position, the leaves became horizontal, so as to present their upper 

 surfaces at right angles to the downward direction of incident light. 



This case was regarded as a sport, but in the common yew many 

 short branches can be found growing erect, and when this is the case the 

 leaves are scattered and nearly erect too. 



But, further, in the yew the leaves arise out of the stem in normal 

 arrangement, say | phyllotactically, and they retain this position when 

 horizontal, for this latter position is acquired by twisting their short 

 petioles. If, however, a shoot grows up vertically out of a laurel hedge, 

 the leaves will be found to be on the § arrangement, while all on the 

 horizontal shoots are distichous or h A similar difference is seen between 

 the leaves of the ivy when climbing, and when the bough grows out freely 

 into the air. This shows that the position of the bough acts more pro- 

 foundly upon the development of the leaves, for it causes them to issue 

 at quite different places accordingly. 



Fasciaiion. — This phenomenon is extremely common, as in asparagus, 

 and many herbaceous flowering steins. In woody branches, it is by no 

 means uncommon in the ash tree. The immediate cause is unknown, 

 beyond the vague term "hypertrophy." It consists of a multiplication of 

 the fibro- vascular cords by repeated branching ; the whole of them being 

 included in the same cellular tissue and epidermis, instead of their grow- 

 ing separately into distinct branches. As a rule it is not hereditary, but 

 it can be so. A common garden nasturtium had its stems partly fasciated, 

 and the peculiarity proved to be hereditary for five years. The cockscomb 

 is an hereditary form of a fasciation of long standing ; Celosia cristata in 

 its natural condition producing a long feathery inflorescence. 



Weeping. — The weeping form of many trees is regarded as a variety, 

 and as a rule can only be perpetuated by cuttings &c. 



As the weeping willow has drooping branches when growing by 

 water, but may have them non-weeping if away from it (as is noticeable 

 in the cemetery of St. John's Wood Chapel, London) ; and the deodar 

 has pendulous branches in England, but as a native on the Himalayas 

 resembles the cedar of Lebanon, atmospheric or terrestrial moisture 

 appears to be the cause ; at least it is a coincidence. None of 50,000 

 seedlings of the weeping elm and ash proved to be able to inherit the 

 habit (Rivers) ; Mr. McNab, however, records the fact that a seedling 

 from a weeping birch was erect for ten years, but assumed the weeping 

 form subsequently. On the other hand, the late Rev. Prof. J. S. Henslow 

 raised a number of seeds from weeping ash trees. The boughs had some 

 slight tendency to droop for two or three years, but they subsequently 

 became erect. 



Spiral Torsion. — When leaves are normally "opposite " and "decussate," 

 as on the common nettle, they may become "alternate," i.e. arranged 

 round the stem singly on a spiral line, as has occurred with that plant. 

 This was a seedling sport ; but this change is of normal occurrence in 

 the Jerusalem artichoke and willow herbs ; such is not so named in these 

 plants. 



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