PANICLE CHARACTERS OF SORGO 9 
fail to reach the next node. Certain varieties always produce 
branches from some of the upper buds, but other kinds branch 
only when the plants are approaching maturity, usually as an effect 
of abundant precipitation after a period of drought. Under normal 
conditions the main culm as well as each branch is terminated by a 
compound inflorescence, a panicle which emerges from the sheath 
of the last leaf, the accompanying blade of this sheath being con- 
siderably shorter than the blades of the other leaves. The panicle 
is joined to the last node of the culm or branch by a specialized 
internode, the peduncle. 
THE INFLORESCENCE 
Panicles on initial culms and those on branches are similar except 
that they may differ in size, climatic and soil conditions which affect 
the general growth of the plant also much modifying the development 
of the panicles. When conditions are favorable during the period 
of development of the panicles, those on the initial culms are large, 
but if conditions are unfavorable during those periods they remain 
small, or they even may not emerge, and the panicles which sur- 
mount branches, which are usually put forth subsequently from 
some of the upper buds of the culms after conditions have become 
more favorable, often surpass in size those on the initial culms. 
The central axis of the panicle is divided into internodes, at the 
nodes arising primary branches, or rays. The internodes are fre- 
quently so short that the nodes are very close together, and the 
rays then have the appearance of being in part in whorls. There 
are usually, however, rays interspersed between the apparent ver- 
ticils. Rays which originate at the nodes of the axis rebranch, and 
branches of the third rank also occur. The arrangement of branches 
on the axis in a varietv of the spreading t}<pe, the Honey (Sugar 
Plant No. 0241466) , is shown in Plate I. 
Racemes having from one to five joints occur at the ends of the 
branches. Racemes of two varieties, Sumac (Sugar Plant No. 0181) 
and Planter (Sugar Plant No. 01816), are shown in Plate II, A. 
The rachises of the racemes in this group of sorghums do not 
disarticulate at the joints. They are hairy in all our varieties. 
Spikelets, which are secondary inflorescences, occur in pairs at the 
joints of the rachis, one fertile and sessile and the other sterile and 
usually pedicellate, except that at the last joint two sterile spikelets 
occur in union with a single sessile fertile spikelet. In most of the 
varieties the sterile spikelets fall off to a great extent before or soon 
after the fertile spikelets become mature. They do not disarticulate 
from their pedicels, however, nor do the pedicels disarticulate at 
their bases; but the latter become dry and rupture at some point, 
whereby the sterile spikelets become free and drop off abundantly. 
The fertile .-pikelet consists of a short floral axis on which the 
following parts, or members, occur in a 2-ranked arrangement : The 
first glume, the second glume, a sterile floret, and a fertile floret. 
The glumes, or outer bracts, are usually somewhat indurate and more 
or less thickened. Before anthesis the first glume partly incloses 
the second, and the glumes together completely cover the other mem- 
bers. In some varieties also in the mature state the glumes consti- 
tute the most conspicuous parts of the spikelet, but in others they are 
67898—26 2 
