6 BULLETIN 1164, U. S. DEPARTMENT OF AGRICULTURE. 
very broad base and a very short, abrupt, blunt "nose" at the apex 
(which is sometimes almost entirely lacking). The average length 
is nearly the same in the two varieties, but the Holdon boll has a 
much greater diameter. The Holdon boll is characterized by a short 
but conspicuous " midlock furrow " extending two to five millimeters 
down from the apex, which is entirely lacking in Pima. The surface 
of the unripe boll in Pima is somewhat shiny, light elm green in color 
(35, pi. 17) and somewhat roughened by the pits at the bottom of 
which lie the rather conspicuous oil glands. In Holdon the boll sur- 
face is paler colored or asphodel green (35, pi, 41), is very smooth 
and not pitted, and the oil glands are very inconspicuous. 6 
Fiber characters. — The fiber of Pima (PI. X, B) averages about 
41 millimeters (If inches) in length, that of Holdon (PI. X, A) about 
29 millimeters (1$ inches). In color the Pima fiber is a pale buff 
(nearest the tilleul buff of Ridgway (35, pi. 40), while that of Holdon 
is nearly white. The weight of fiber per seed (lint index) is consider- 
ably greater in Holdon than in Pima. 
Seed characters. — In Pima (PL XI, B) much of the seed coat is 
naked, the fuzz, which varies in color from dull green to brownish 
white, being largely confined to the two ends. The Holdon (PI. XI, 
A) seed is entirely covered with bright white fuzz. 
CHARACTERS OF THE FIRST-GENERATION HYBRID. 
In a field of either type of cotton, first-generation upland-Egyptian 
hybrids are always conspicuous because of the vigor and fertility of 
the plants (PL II). The conjugate generation (F,) of Holdon X Pima 
exhibited heterosis or intensification in most of the size characters. 
It was intermediate or nearly so in color and texture of the leaves 
(PL IV), divergence of the teeth of the involucral bracts (PL V, fig. 2), 
dentation of the calyx and abundance of oil glands in the calyx 
(PL VIII, fig. 2), color of the petals, average number of boll locks, color 
and surface of the boll (PL IX, fig. 2), and color of the fiber. It ap- 
proached the Holdon parent in the red color of the leaf callus, in the 
length of the filaments of the stamens (PL VIII, fig. 2), and in having 
the seeds completely covered with fuzz (PL XI, E). Characters in 
respect to which the conjugate generation approached the Pima 
parent were: Deeply lobed leaves (PL IV), relative freedom from 
hairs of the petiole and under surface of the leaf, connate and not 
very deeply toothed involucral bracts (PL V, fig. 2), presence of a 
petal spot (PL VII, fig 2), although the spot was much smaller, 
streakier, and less deeply colored than in Pima, bright-yellow color of 
the anthers, long pistil, relatively long stigmas (PL VIII, fig. 2), 
pointed bolls (PL IX, fig. 2), absence of a midlock furrow, and rela- 
tively long fiber (PL X, E)? 
Two characters were noted in the first generation of this hybrid 
which may be regarded as extraparental, although not belonging to 
6 In the bolls of upland cottons, as was pointed out by Balls<.{, p. 59) the glands lie beneath several 
layers of subepidermal parenchyma. 
7 It war noted by Balls in Egvpt (.',p. 73) and by Cook in Arizona (11, pp. 14, 15) that first-generation 
Egyptian-upland hybrids frequently surpass in length of fiber the longer fibered (Egyptian) parent. An 
interesting example" of absence of intensification of this character in a first-generation hybrid of Kekchi, a 
Central American variety of the upland type, with American upland cotton is reported by Cook (ibid, 
p. 14 j. 
