PANICLE CHARACTERS OF SORGO 15 
that no definite values can be assigned to any variety. The approxi- 
mate length of primary branches as compared with the length of 
the panicle itself is in a measure adaptable, its relation to the form 
of the panicle having already been noted. 
The primary branches or rays from the lower nodes of the axis 
are more or less devious, and in one variety they are somewhat 
spirally twisted. The primary, secondary, and ultimate branches are 
somewhat angular in some varieties, though not in others; this 
difference is then distinctive. As a rule, branches in the effuse types 
are less angular than those in the more compact types. As in the 
case of the axis, the branches in certain varieties are sometimes tinted, 
the color resembling that of the glumes of the fertile spikelets, 
though in others such coloration is not evident or is very much 
less marked, this also being true of the rachises of the racemes. 
PUBESCENCE OF THE BRANCHES 
In certain varieties the pubescence on the primary and secondary 
branches is limited mainly to hairs on their bases and in the axils, and 
to fine hairs, bristles, or teeth fringing the ridges. In others these 
branches are more or less hairy throughout. In certain varieties 
also the pubescence is uniform or mainly so in the striations, and 
in others the hairs on the angles are longer or more abundant. The 
axils may be somewhat barbate or pilose, this pubescence sometimes 
also extending over the flattened surface of the branch adjacent to 
the axis and sometimes to the angles as somewhat longer hairs. The 
ultimate branches present three distinct types regarding pubescence : 
(1) The ciliate on the angles or ridges, (2) the scabrous, and 
(3) the glabrate. 
THE FERTILE SPIKELET 
The fertile spikelet exhibits greater differentiation than the panicle 
itself, as such, or the axis or branches of the panicle, the differences 
relating to the form and size of the spikelets ; the form, texture, thick- 
ness, nervation, pubescence, color, markings, and manner and extent 
of opening of the glumes; the presence or absence of the awn; the 
form, color, and comparative size of the caryopsis; and varia- 
tions in some of the features of the caryopsis. The awn, as well as 
some of the other features of the spikelet, is present at an early stage, 
even before the panicle emerges from the sheath. Investigation of 
the spikelet is much facilitated if it is magnified, a reading glass or 
hand lens enlarging to two or four diameters being adequate for 
observing the form, although it is desirable to have greater magni- 
fication for the purpose of examining the spikelets in regard to 
nervation and pubescence. A binocular dissecting microscope has 
been found serviceable for these purposes in the laboratory, but a 
hand lens of good quality, enlarging to about 8 diameters, may also 
be successfully used. Such a lens has the advantage of being easily 
transported and is therefore better adapted to field use. The small - 
ness of these spikelets, making magnification necessary in order to 
study them properly, somewhat lessens their value for purposes of 
identification. On the other hand, the large number of their features 
