TO BIRD’S-EYE FORMATION IN THE Woop OF TREES. 27 
protruding root. In Plate X., Fig. 27, we have one of those 
patches more highly magnified, and in it may be distinctly seen 
a connection between the cork-cambium of the stem and the 
cork-cambium of the root. The piece of cork-cambium seen on 
the left-hand side of the figure belongs to the stem. At the base 
of the lenticular patch this cork-cambium forks, one branch 
running round the outside, while the other branch passes round 
the inside of the patch at the top of which the branches unite 
and continue round the periphery of the medullary ray-root. 
This lenticular patch of tissue is a portion of the parenchyma- 
cone seen in Plate IX., Figs. 23 and 24, which has ultimately 
been pierced through by the outgrowing root. 
These roots are not permanent structures, but die off at a 
comparatively early period after they have pierced the periderm, 
but before this happens a cork-layer is formed across their bases 
by a branch from the cork-cambium of the stem given off shortly 
before it forks around the lenticular patch of tissue referred to 
above. This cork-cambium may be distinctly seen in Plate X., 
Fig. 29. The old root is cut off therefore much in the same 
way asa leaf. Sorauer gives a figure! of a portion of stem of 
maple on which bird’s-eye wood (Maser-holz) has been formed. 
The bark has been removed to show what the author calls the 
wooden-pegs (Holz-Spiese). At the top of the figure they are 
shown in cross section. The structure presented in that figure 
recalls very strongly what is seen in our Plate IX., Fig. 19, while 
the projecting woody-cones resemble the one seen in Plate IX., 
Fig. 22. Whatever other causes may produce Bird’s-eye Maple 
it would certainly seem that lignified rhizogenous medullary rays 
can bring about its formation. 
Apple. 
A very curious and striking example of an abundant production 
of adventitious outgrowths was pointed out to me by the Regius 
Keeper on two small apple-trees in the Royal Botanic Garden. 
All their stems and branches were covered by remarkable coral- 
like excrescences, especially noticeable at the base of both spur- 
shoots and elongated shoots. Plate X., Fig. 31, gives the 
1Sorauer, Pflanzenkrankheiten, 2nd Ed., Vol., I (1886), p. 732, Fig. 38. 
