CROWN-ROT OF FRUIT TREES: HISTOLOGICAL STUDIES 509 
Fig, 9. Much like Fig. 7, but with larger groups of living cells in the cambium; 
more definite radial ruptures are evident in the inner phloem. On the right all of 
the phloem and cambium between the clefts and the wood are dead. 
Plate XXII 
Displacement of initially killed tissues by regeneration-growth. Collected two 
weeks after the material used for Plate XXI; all from apple. 
Fig. id. A development from an injury like that shown in Figs. 6 and 7. All 
living cells have grown and compressed the dead material. Living cells proliferate 
outgrowths into the dead masses. Regeneration tissue is all parenchymatous; 
it divides in all planes. 
Fig. II. Similar to Fig. 10; in neither of these instances are living connections 
evident between the bark and wood. 
Fig. 12. Different from the two preceding chiefly because some of the cambium 
has survived. Even where the cambium is killed, frequent living cells are found to 
bridge the gap. Regeneration has repaired many holes that resulted from the 
shrinking of groups of dead cells. 
Fig. 13. Seems to be a later stage of an initial injury of the type show in 
Fig, 6; both at the right, where the cambium is involved, and at the left, where the 
inner phloem is affected, proliferating cells connect the wood with the bark through 
mantle of dead tissue. 
Fig. 14. Though the old cambium (oc) was only slightly injured, a new one 
has begun to develop (cc) in the regeneration tissue of the inner phloem. Initial 
injury in the older phloem was very severe, yet the living portions of it are compress- 
ing the dead masses by growth. 
Fig, 15. From the type shown in Fig. 8; new cambium (cc) is forming in re- 
generated tissue of the inner phloem, and the former cambial line is discolored. 
The outer phloem and cortex are almost wholly isolated from the inner bark by a 
ragged layer of dead tissue. Occasional living cells occur in the dead mass. 
Fig. 16. Derived from a portion that was less injured than that shown in Fig. 
6. Living tissues dominate, and new cambium (cc) has become established. 
Fig. 17. Much like Fig. 15, excepting that the injury is much more severe in 
the old cambium. 
Plate XXIII 
Final disposition of much of the initially killed tissue. Collected a month after 
that shown in Plate XXII; all from apple. 
Fig, 18. Late stage of a type shown in Figs. 7 and 9, Former position of the 
cambium (oc) and its present location (nc). A considerable layer of new wood 
{nw) has developed, and a new phloem (np) is also noticeable. In the phloem 
the dead masses are localized near the boundary between the old and the new phloem, 
some extending into the new phloem toward the cambium just as dead streaks 
extend into the new wood from the injury outside of the old wood (ow). 
Fig, 19, From the middle toward the right of the figure the new cambium (nc) 
is only faintly indicated. Injury at the old cambium {oc) is not as conspicuous as 
in Fig, 18, but it is of wider extent. Initial injury occurred throughout the old 
phloem and was very severe. 
