66 R. A. EMERSON 
One of these forms, known as weak purple, type Ib, is intermediate 
in certain respects between purple and sun red, and in other respects 
between purple and dilute purple. Plants of this type, prior to the 
flowering stage, frequently resemble sun reds more than purples. The 
pigmentation of the sheaths is less intense than with purples, and in 
some instances less than with strong sun reds. There is, however, sooner 
or later a tendency for pigment to develop on the stalk beneath the 
sheaths (Plate V, 2). In this respect weak purples resemble dilute purples 
as the latter often appear in a late stage of their development. The 
anthers of weak purples are usually full purple, like those of purples 
and dilute purples, in which respect they show no resemblance to sun reds. 
A second intermediate form, known as weak sun red, type IIb, stands 
between sun red and dilute sun red. The sheaths and husks are less 
extensively and less intensely pigmented than is true of full sun red, and 
yet exhibit much more color than in dilute sun red (Plate V, 4). The 
anther color of weak sun red is like that of both sun red and dilute sun 
red. 
While the difference between the extreme sun-color types, sun red and 
dilute sun red, is probably only a quantitative one — as is also presumably 
true of the difference between purple and dilute purple — little difficulty 
is experienced in separating sun red from dilute sun red plants on the one 
hand, or purple from dilute purple plants on the other. Frequently, 
however, it is difficult, or even impossible, at early stages of plant growth, 
to separate sun reds from purples. The existence of such intermediate 
forms as weak purple and weak sun red adds materially to the difficulties 
of classification. In fact, correct classification of all these types by inspec- 
tion alone is possible only at the flowering stage. For certainty in classi- 
fication, even at the flowering stage, environmental conditions, particularly 
soil fertility, must have been favorable thruout the growing period of the 
plants. While infertile soil exaggerates the difference between dilute 
sun red and green, by bringing about an excessive development of red 
pigment in the one type while no color develops in the other, on fertile soil 
only are revealed the finer distinctions between sun red, weak sun red, 
and dilute sun red. It is perhaps fortunate that the genetic relations off 
these several types are such that ordinarily not all of them occur in a 
single progeny. 
