A BRACHYTIC VARIATION IN MAIZE. 9 
branch immediately below until the uppermost branch, borne in the 
axis of the second leaf from the top, has but two nodes. Thus each 
branch has one more internode than has the portion of the main culm, 
which is immediately above it. Contrary to Montgomery (13), this 
does not hold true for maize, but the relation may have been modified 
through brachysm. There is some evidence to show that the total 
number of nodes is increased when the main culm is brachytic, and if 
this fact held true for lateral branches it would account for the differ- 
ence between maize and teosinte in this respect. When the ear stalk 
is lengthened, as in the tropical varieties previously mentioned, it be- 
comes possible to ascertain the number of nodes with accuracy. In 
these cases it has been found that there are 15 or more nodes, while 
only 5 or 6 nodes of the main stalk are above the ear-bearing branch. 
Although the pistillate inflorescence of maize affords the most 
striking example, there are indications of brachysm in the formation 
of the male inflorescence. If it is assumed that the internodes of the 
main axis are shortened and the terminal spike is formed through a 
reduction of lateral branches, this would constitute a still further 
stage of brachysm. 
Brachysm of the main culm might be considered an example of 
homoeosis (12), but on this hypothesis it is difficult to understand the 
absence of any tendency for the brachysm of the upper branches to 
become transferred to lower ones, a step much more direct than that 
involved in transferring this characteristic to the main culm. There 
is, however, some support for this view in that several of the 
brachytic plants developed pistillate flowers in the otherwise unal- 
tered staminate inflorescence, and although none of these pistillate 
flowers developed seed this fact suggests that an association exists, 
however slight, between brac}'tic internodes and the development 
of female flowers. 
ASSOCIATED CHANGES. 
Mutations in most organisms are not confined to single characters, 
but alter the expression of many and frequently unrelated parts. 
Usually a particular character is changed greatly, serving to divert 
attention from minor changes in other characters. Careful examina- 
tion of many characters of an individual which has mutated obvi- 
ously in a single one often reveals the presence of the other changes. 
With the intention o»f determining whether other characters than 
internode length had undergone alteration in the original brachytic 
plants, careful measurements were made of other organs. Only two 
other changes were observed. The ears were flattened somewhat, 
doubtless due to the mechanical pressure of the large number of leaf 
sheaths. Such an alteration can not be considered as mutative, since 
it is an indirect manifestation of the brachytic condition. The other 
16071°— 21 2 
