AND 



317 



bud and a leaf adjacent to it remained quite fresh. By the 20th 

 all four leaves were almost dead, with the exception of the bases 

 of the blades. The terminal bud remained perfectly fresh until 

 the 29th, when the whole was dead. Duration 17 days. A simi- 

 lar specimen not moistened totally perished in 2 days. 



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leaves, as Borago officinalis, JRumex crispus, Sisymbrium Alliaria, 

 Lychnis dioica, &c, have only their internodes wrapped up in satu- 

 rated blotting-paper, the leaves generally soon wither and perish, 

 but the internodes remain green and fresh for long periods. 



A branch of Borage having two internodes was wrapped up on 

 June 8th, 1876. On the next day the leaves were much faded, 

 but the stem was quite firm. On the 10th the upper part of the 

 leaves was brown, brittle, and dead, but no change had taken place 

 in the stem. By the 12th the leaves were entirely withered, ex- 

 cepting a small portion at their bases. On the 13th the leaves 

 were quite dead. The internodes remained firm, green, and fresh. 

 They thus continued until July 10th. They then decayed slowly. 

 Duration 5 weeks and 3 days. 



A similar specimen not wrapped up was perfectly dead in 2 

 days, the previously juicy stem being now dry and collapsed. 



The long time during which the leaves remained green, of the 

 first described of these specimens of Borage, clearly proves that 

 the supply of water must have been obtained through the epi- 

 dermis of the internodes to balance the transpiration. 



8ymp7wricarpus, or Snowberry. — A shoot had one internode 

 trapped up, with four leaves beyond it exposed. After 3 days 

 the lower pair of leaves were dying, but the upper pair were fresh. 

 After 8 days all the leaves were dead ; but the internode remained 

 fresh several days longer. 



A second and similar specimen had also four leaves exposed ; but 

 they were below the internode which was wrapped up. The order 

 of decay was in this case reversed ; the two lowermost or furthest 

 from the wet internode died first, those nearest to it last. 



The above are selected from a large number of experiments to 

 illustrate the fact that herbaceous internodes readily absorb mois- 

 ture in the endeavour to supply the leaves with water for trans- 

 piration, but that the demand is usually much greater than one or 

 a few internodes can furnish : hence the leaves soon begin to die 

 back from their apices to their bases. In addition to such supply 

 aa they can for a time give to the leaves, the experiments prove 



MM*. JOUEX. — BOTANY, YOL. XYII. 2 A 



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