142 AJERIAL VINE ROOTS. 



place in the stems, and, favoured by the moist warm atmosphere of the 

 Vinery, bursts through the bark in the form of fibres, continuing to 

 lengthen tiU they are checked by drought. An extraordinary pro- 

 duction of these aerial roots was observed to take place whilst an 

 experiment was being made with a Black Hamburgh Vine, in the garden 

 of the Horticultural Society. It had grown vigorously in an open 

 border, when, being in freedom, no rootlets broke from the shoots. 

 A 3-light frame was placed over this plant, and made as air-tight 

 as possible ; the sashes were never opened, except to supply water to the 

 roots ; a thermometer inside the frame was generally raised every day 

 above 140° by sun heat. An Orchid placed in a shaded part of the 

 frame was killed in two days, yet the Vine continued to grow. 

 It burst its wiater buds rapidly into shoots, and almost as soon 

 as the buds on these young shoots were formed, they also pushed, 

 weaker of course, and agaia stUl weaker growths proceeded from 

 these secondary shoots. Meanwhile a vast number of roots issued 

 from the shoots trained horizontally near the glass, and these 

 roots soon reached the surface of the ground, which became 

 matted by them, for it was moist, and for a little way sufficiently 

 warm, by reason of the sxm.-heated air in the frame. But with 

 regard to the old roots in the earth, the case was very different. The 

 heated air of the frame could but slightly affect the soil at the depth 

 where they were situated, whilst those extending beyond the limits of 

 the fram.e were of course entirely beyond its influence. 



The consequences of a profusion of branch-roots on the Vine are 

 these ; they absorb moisture from the air in the house, and so tend to 

 increase the breadth of the foliage and swelling of the berries ; even 

 the thickness of the wood is considerably increased by them, for it is 

 not uncommon to see a Vine branch smaller at the base than higher 

 up ; in short they are sources for the supply of nourishment, 

 but they are sources which dry up when they are most wanted. 

 They assist in forming a widely expanded foliage during moist weather; 

 and when dry weather demands a greater supply, to compensate for 

 increased evaporation from broad foliage, the stem-borne rootlets 

 contribute nothing. To their precarious supply may be partly attributed 

 the shanking and shrivelling of fruit. They should be checked in time 

 by allowing the air in the house to become occasionally dry. But above 

 all things, their appearance should be prevented by maintaining a due 

 proportion between the temperature of the air and earth in which 

 the Vines are plunged. 



The effect of aeiipiciallt warmiks a Vine bokdeb, in this country 

 has been seen in many instances; not the least instructive of which 

 occurred to Mr. Purday, the eminent and scientific gunsmith. In his 

 garden at Bayswater, a Vinery was filled with wood and produced an 

 abundance of excellent Grapes in little less than two years, by merely 



