10 R. A. EMERSON 
of medium size. No other stock of purple has been used in the crosses 
described later in this account, and the writer has never seen this color 
type in cultivation outside his own cultures. A sample of dent corn of 
apparently the same color type was seen at a national corn exposition 
in 1909. A stock of purple was obtained from Dr. Gernert in 1914 but 
was not used in genetic studies. Another stock of purple was received 
more recently (1919) from Messrs. Collins and Kempton, the seed having 
come originally from Bolivia. 
Seedlings of the purple type are usually indistinguishable from those of 
types II, III, and IV (described more fully under type IVa, page 12), altho, 
unlike the other types, they develop some color when grown in darkness. 
Half-grown plants of type I usually have the lower sheaths prominently 
colored, in which respect they exceed type II plants in intensity of pig- 
mentation and are sharply differentiated from types III and IV. At the 
flowering stage, plants of type Ja have much purple color in nearly all 
parts, such as the culm, the brace roots, the leaf sheaths, the husks —even 
the inner ones — the cob, and the staminate inflorescence including the 
rachis, the spikelets, and the anthers (Plates I, 1, and V, 1). In some 
cases the color extends over the whole leaf, and it is always seen in 
the midrib. The purple pigment of type Ia develops in local darkness, 
as has been shown by covering various parts of growing plants with several 
thicknesses of heavy black paper (Plate VIII, 1). The color persists in 
mature plants with slight fading in the outer parts due to weathering (Plate 
VII, 1). The pericarp of type Ia is either colorless. red, or cherry, and 
the aleurone is either purple, red, or colorless. With red aleurone the 
anthers are reddish purple, and with cherry pericarp they are usually 
very dark purple, almost black (Plate I, 2 and 8). 
A subtype of purple known as weak purple, or type Ib, is similar to Ia 
but the pigmentation is less intense, particularly in the culm and the 
inner husks (Plate V, 2). In early stages of growth it is often difficult 
to distinguish Ib from Ila. The anthers of Ib are usually deep purple, 
as are those of Ia, and the pericarp is the same as for Ia. Another sub- 
class of purple, Ig, is like Ia except that the anthers are green (Plate I, 
4) and the pericarp is red or colorless, never cherry. The aleurone color 
is the same as in Ia. 
