36 BULLETIN" 1477, U. S. DEPABTMENT OF AGEICULTUBE 
where large branches have been headed back or removed. Where growing 
conditions are poor, the branches of trees of this variety are slender in pro- 
portion to their length, and more so than with most other varieties which 
produce twigs rather than spurs. With the slenderness of branches is the 
tendency to be barren after bearing a crop of fruit, to bear light crops of 
small fruit, to branch little, and to lose many twigs soon after they are pro- 
duced (pi. 38, D). 
Fruit is borne almost entirely at leafless nodes of 1-year twigs and on 
1-year-old spurs. The bearing spurs are usually without leaves, except that 
occasional bearing spurs on a thrifty tree produce twigs. 
Wounds left where large branches are removed heal very slowly ; therefore, 
pruning should be confined to the smaller ones as much as possible. 
NEW OR LITTLE-KNOWN VARIETIES 
Burton. — Trees of this new domestica variety resemble the Imperial Epineuse 
both in form of tree and in the growth of spurs and small branches (pi. 39, A). 
In general, a pruning practice suitable for the Imperial Epineuse appears 
to be suitable for the Burton. Near Vacaville, Calif., the only section where 
this variety has been in bearing, it has borne heavy and regular crops of 
fruit for a number of years. Because of its productiveness, somewhat more 
pruning is required to maintain the desired wood growth than is needed by the 
Imperial Epineuse, which in many localities is a light and irregular bearer. 
Stuart. — This also is a domestica variety. The trees appear to be almost 
identical with the Imperial Epineuse in their habits of growth, and therefore 
the same pruning practice is applicable to both. Bearing trees have been 
observed only in the north-central part of the San Joaquin Valley in Cali- 
fornia. Like the Burton, trees of this variety have been more prolific than 
those of Imperial Epineuse growing beside them. Its fruit also resembles the 
fruit of the Imperial Epineuse very closely, whereas the fruit of Burton is of 
an amber color and in shape resembles the Agen more than the Imperial 
Epineuse. 
Sweetheart. — This domestica variety has been observed near Courtland, 
Calif., where it originated. This is the only place it is growing commercially. 
It is included here on account of the peculiar habits of its fruiting wood. The 
tree is moderately thrifty, very prolific, has upright spreading open top, and 
produces and retains numerous spurs and spurlike twigs (pi. 39, B). The 
spurs or spurlike twigs form thickly along the 1-year-old wood and where 
they are not broken off or injured by shade are retained for a number of 
years. They are slender and branch freely, and considerable terminal growth 
takes place on each of the branches. There is often a main spur leader, how- 
ever, which somewhat outgrows the other branches of the spur (pi. 39, C). 
In shaded places there are few branches on the spurs, although the tree is 
naturally open, and injury from shade seldom results. The fruit is borne at 
leafless nodes of both spurs and the twigs which grow from them in all parts 
of the tree. 
Becky Smith. — Bearing trees of this Japanese sort have been observed only 
in the fertile, unirrigated section near Vacaville, Calif. The tree is upright, 
vigorous, and inclined to produce numerous framework branches if headed 
back. Otherwise it branches little, except for the production of numerous 
small fruiting branches and twigs. These are retained along the entire length 
of the branches. The twigs grow to several inches in length and are well set 
with short prolific spurs. Pruning to develop numerous secondary branches 
and heading back and thinning out to maintain vegetative vigor and to prevent 
shading of twigs in the interior of the trees appear to be desirable in pruning. 
COMPARISON OF BEHAVIOR OF PLUMS UNDER EASTERN AND 
WESTERN CONDITIONS 
In plum-growing sections of the United States other than where 
these studies were conducted the benefit derived from the observations 
presented will be of a fundamental nature only. In those regions, 
bearing plum trees of the same varieties as those considered here are 
pruned little, if at all, and only rarely to the extent commonly prac- 
