186 OBSERVATIONS ON THE CALIFORNIA VINE DISEASE 
fiber bundles seems to be produced and the phloem is of normal 
size. 
(d) The production of suber is scant, and occurs at about the 
position normally occupied by the second bast fiber bundle. The 
phloem is much reduced in size, and the bast fiber bundles are 
obsolete. | 
(е) The suber is continuous: it has not always formed immedi- 
ately below the pericycle, but frequently several rows of phloem 
cells beneath it. 
(f) The suber is continuous in the immature spot and lies well 
within the phloem. The bast fiber bundles, which are normally 
developed at the edge of spot, gradually dwindle down to a 
fragment of one, and disappear. Following the decrease in the 
number of the bast fiber bundles there occurs a parallel decrease 
in the size of the phloem; when the bundles disappear the phloem 
is about one half its normal size. (PLATE 5, FIGURE 2.) 
Cane.—The canes on which the immature spots I have just 
described occurred were all morphologically imperfect. Могрһо- 
logically mature tissue would interchange, by gradations, with 
morphologically immature tissue, and the immature spots would 
form a break in one or the other, or, as it were, the connecting 
link between the two. Where the formation of the tissues was 
the least perfect the wood fascicles and their corresponding 
phloems were much undersized, and no bast fiber bundles were 
formed. 
І have just shown that in diseased canes the morphological 
variations are considerable, and the reader will naturally expect, 
as а consequence, considerable variation in the cell pathogno- 
monics. These variations, though in themselves interesting, are 
not sufficiently important to warrant particular mention, and 
I shall, therefore, confine my attention to a general description, 
taking for type a section through a cane in which the cells show 
considerable disease. Тһе part of the cane most diseased will be, 
as a rule, the immature spot. 
Dowlen says, in describing the histology of diseased canes, 
that in “those canes which have one side ripe and the other side 
unripe, the tissues of the ripened portion are almost always wel! 
supplied with starch—some starch will always be found—whilst 
