430 
Journal of Agricultural Research 
Vol. XXXI, No. 5 
the oxidizing brought out the tender fibers in strong relief. The 
early preparation of the leaf to resist exposure to the wind would 
require this formation of the embryo bundles within the zone of cell 
division where complete absence of light prevails. 
Gradual exposure to the light as the group of leaves is pushed 
upward would be followed by the completion of the thickening and 
hardening of these bundles and the full development of the water¬ 
carrying tissues, but without gain in length. 
(2) Branner also found (2, p. JflO) that the total number of bun¬ 
dles was about uniform throughout the lower and upper portions 
of the trunk and that while branches were being continuously given 
off for the formation and support of new leaves, the number of 
bundles continuing into the main axis remained substantially uniform. 
(3) Branper further states (2, p. Ifl6 ): “A palm trunk may grow 
laterally as long as the fibro-vascular bundle divisions of the given 
part are in connection with active fronds.” This in practice means 
that the cone of growth coincides with the altitude zone of active 
leaves, which is pretty well confirmed by field observations in 
California and Arizona, 
OFFSHOOT BUDS AND FLOWERING BUDS 
Morphologically, every date-palm leaf should produce in its axil 
either a vegetative bud or a fruit bud, though many fail of more 
than rudimentary development. The earliest buds on seedlings are 
invariably vegetative buds, giving rise to offshoots so low on the 
trunk that they often may become self-rooted in the soil. Offshoot 
buds may continue to be produced for many years, especially in 
damp coastal climates, but tney usually are replaced permanently by 
flowering buds after a few years. These flower buds may be produced 
in an almost unbroken succession, but with a heavy production of 
fruit by the female trees one year, few or no fruit spathes may develop 
the next year. The staminate and pistillate flowers are borne on 
separate trees. 
The fruit spathes always arise within a few leaves, often only 
six or eight, of the bud center, and usually develop in centrifugal 
order, the highest and youngest first, then the next older, spirally 
downward and outward. All are in closest proximity to the growth 
center, and the growth of the fruiting stalk is basipetal, as is that of 
the leaves. Frequently the lower and later flowering heads, though 
really the oldest in point of origin, seem to be one side of the most 
active life current and fail to receive the nourishment to bring them 
to full fruition. This is especially true in the case of male palms, 
where the late flowers are often abortive. 
The interior substance of the young date-palm trunk, when tested 
has always shown the reaction for starch. To what extent this is a 
storehouse of reserve food is a question for further study. 
The foregoing rather extended account of the structure and habitat 
of the date tree has seemed necessary to an understanding of the un¬ 
expected and remarkable temperature reactions which were observed 
on inserting thermometers into the heart of the palm trunk—some 
into the lower trunk and others into the actual growth center. 
