508 MISS ISABEL MCCLATCHIE ON 
but they were all feeble and never greater than half a centimetre in length. 
Text-fig. 164 shows the specimen which had the greatest development of 
roots (the paired arrangement is unusual). 
(^)—Four plants showed signs of roots, but all were feeble. 
Iu these experiments the roots were always much less numerous and 
generally smaller than in the eases of accidental wounding, previously 
referred to. This may be attributed to the fact that not only were the 
wounds less serious but the plants also maintained their vertical position, 
The latter condition has already been shown to be unfavourable to root- 
development. 
à I6b 
lGa AQ J 3 
Fia. 16a.—Plant showing arrested root-development, owing to a change in the 
direction of bending, 
Fra. 16 b,—Stem showing a cut made above the second node and the resulting 
development of roots, 
В. Twenty plants were wounded below the nodes; the wounds were 
identical in character with those made in experiment A. 
(a) Ten plants were wounded below the second node. 
(b) ” 33 99 ” third 
Result. | 
In no case was there any signs of root-development. This result is in 
keeping with the fact that in healthy plants roots generally appear 
immediately above and not below the nodes, 
ur 
C. А nearly mature plant was bent sharply down at a point a little above 
the second node, and the upper portion of the stem was pegged down to lie 
horizontally along the soil as far as the fifth node. From the swollen 
undersides of the nodes in contaet with the soil adventitious roots developed 
in large numbers. They penetrated the soil and produced lateral roots. In 
the meantime the tissues had died at the bend in the stem, although the stem 
itself remained unbroken. The horizontal and upper portions of the plant 
seemed none the worse for being cut off from the primary root-system, 
