PANICLE CHARACTERS OF SORGO 11 
THE PEDUNCLE 
There are two types of peduncle in regard to form, the straight 
and the recurved. Various degrees of curving are always in evi- 
dence in the variety, and there are always panicles having uncurved 
peduncles, as was indicated by Ball (2). The number curved is 
frequently only a small proportion of the entire number in the field. 
Evidently a relation exists between soil or seasonal conditions and 
the amount of recurving. Populations of which the original source 
of seed was the same, when grown in different plats and in different 
seasons, have shown diversity in the number of recurved panicles 
present. This lessens the value of the feature. It is nevertheless 
useful, as it is very obvious when it occurs, and it has been employed 
by nearly all writers. 
Peduncles also show differences along varietal lines in regard to 
length. They originate at the last node of the culm where the last 
leaf sheath or boot, which covers them to a greater or less extent, 
also originates. As the boot also varies in length, the peduncle may 
be of considerable length but have the appearance of being short on 
account of the length of the boot. Fairly well-marked differences 
are to be seen between varieties both in length of the peduncle and 
the extent to which it is exposed. Although the extent of exposure 
has the disadvantage of being somewhat influenced by climatic con- 
ditions, it is dependent upon the relative length of adjacent parts 
that develop at about the same time and is therefore adaptable, 
especially when varieties are chiefly determined in the field. 
CONTRASTED PANICLE CHARACTERS 
The most striking contrasts exhibited by panicles are : ( 1 ) Vary- 
ing degrees of compactness, resulting from variation in the length 
of the axis and its branches and in the length of the internodes of 
both, and (2) variations in form. Various types of panicle are 
shown in Plates III to VIII, their relative size being indicated by 
the 1-inch scale in the illustrations cited. In the most spreading types, 
when the seeds have reached complete development both the axis and 
branches are relatively long, the branches of all ranks are well sepa- 
rated, stand out more or less from the axis, are bowed, and are occa- 
sionally pendent at the extremities. On the other hand, in the com- 
pact types, which are at the other extreme, all these characters are re- 
versed, the axis and the branches, as well as their internodes, being 
shortened, the branches being somewhat rigid and cleaving more or 
less to the axis, and the seeds being crowded together. Between the 
two contrasting types there are types intermediate in regard to de- 
gree of compactness. Although much heterogeneity exists among 
these, the branches in all are more or less shortened, and they may 
be considered together under the head of the contracted class. All 
types are subject to fluctuation, and all also undergo progressive 
natural changes which alter the apparent degree of compactness 
from the time the panicle first emerges until after the seeds are 
mature. These alterations are especially noticeable in the more 
effuse types, being due in part to a natural tendency of expansion in 
the panicle and in part to climatic influences. Pulvini occur in the 
axils of the branches, though they are better developed in the spread- 
