PANICLE CHARACTERS OF SORGO 21 
Soil and climatic conditions often modify colors considerably. 
For this reason some varieties when grown in different localities and 
in different seasons often show some variations in tints and shades. 
Colors also fade to a certain extent, the greens owing to chlorophyll 
being largely lost when panicles become mature or are dried for 
future reference. Other tints also become more or less dull on being 
dried and with age. All colors mentioned in this bulletin were 
checked in spikelets of at least three seasons, but under certain con- 
ditions of environment the tint or shade may differ from that given. 
PUBESCENCE 
The fertile spikelet in all of the varieties studied becomes hairy at 
an early stage, and in the mature state certain kinds show pronounced 
differences in the abundance and the coarseness of the pubescence on 
various parts. Differences in the persistence of the hairs are also 
to be noted, glumes much indurated ordinarily being less per- 
sistently hairy. This is shown in Plate II, B, in which the Planter 
variety (Sugar Plant No. 01816) is represented, the second glume 
being more indurate and, as will be noted, less hairy than the first. 
As compared with those on the rachis segment, which usually remain 
with considerable handling of the panicles, hairs on the glumes are 
usually less persistent. The term " callus " has been used to desig- 
nate the slightly elevated or projecting base of the first glume. The 
pubescence on this portion of the glume in most varieties consists 
of somewhat tufted hairs, which persist more strongly than those 
on the back of the glume. In some kinds, however, the hairs on both 
the back of the glume and on the callus persist strongly, while in 
others they fall off readily. In some forms hairs on the upper fourth 
of the first glume persist much more tenaciously than those on the 
remainder, this being shown in the variety known as Gooseneck. 
The following distinct differences between varieties are therefore to 
be noted : (1) Certain ones which naturally shed nearly all the hairs 
of the glumes, including the basal hairs (PL XII, A) ; (2) one or 
more which retain tenaciously hairs on the upper fourth of the first 
glume, but shed most of the remainder of the pubescence (PL XIII, 
A) ; (3) some kinds in which a greater part of the hairs on the back 
of one or both glumes strongly persist (PL II, B, 1, and PL XII, 
B) ; and (4) a number of varieties in which hairs on the callus, or 
the basal hairs, persist much more strongly than the remainder (PL 
XII, C). In some varieties the basal hairs are coarser than those on 
the back of the glumes, while in others they are about the same, this 
making a fifth point of difference. The latter, however, does not 
constitute a very well marked difference. 
The minute bristles on the lateral nerves of the first glume vary as 
to coarseness, tenaciousness, and color. In some types they are 
thickened, more or less depressed at their points, and deeply colored: 
in others they are more hairlike and colorless: and in still others they 
are intermediate between these two in regard to coarseness and are 
either colorless or only slightly tinted. In a fourth class of varieties 
such bristles are lacking or found only rarely. The keel of the 
second glume usually also bears these minute bristles, these being 
persistent in certain varieties and in others being shed entirely or in 
part before the seeds are mature. 
