478 
GENETICS: F. M. SURFACE 
lated till the fringes appears. As above, they are largest when c and c' 
are as nearly as possible coincident and vanish as horizontal fringes at 
the maximum; for the effective parts of c and are component halves 
of the same diffracted beam from the sht 
It is interesting to observe, since interference*^ also occurs when one 
of the superposed spectra is inverted on a line parallel to its length, that 
such diffraction is demonstrable in case of homogenous light, even 
when the sht is absent. 
A fuller report of this work has been presented to the Carnegie 
Institution of Washington, D. C. 
^Phil. Mag., 22, 118-129 (1911); Carnegie Inst. PuhL, No. 149, Chap. VI. 
"^Physic. Rev., July, 1916; Science, 42, 841 (1915). 
^Amer. J. Sci., 40, §4, 491 (1915). 
ON THE INHERITANCE OF CERTAIN GLUME CHARACTERS 
IN THE CROSS AVENA FATUA X A, 
SATIVA VAR. KHERSON 
By Frank M. Surface 
BIOLOGICAL LABORATORY, MAINE AGRICULTURAL EXPERIMENT STATION 
Received by the Academy, June 30, 1916 
The investigation reported in the present paper^ deals with the inherit- 
ance of certain characters of the flowering glumes in a cross between 
a wild oat Avena fatua and a cultivated variety (Avena sativa). The 
cultivated oat used is a selection from the Kherson variety. Both 
parent strains have been grown as pure lines for five years and are known 
to breed true. 
The parent varieties used in this cross possess the following contrasting 
glume characters. 
CHARACTEIi 
AVENA PATUA 
AVENA SATIVA VAR. KHERSON 
Grain color 
Dark brown or black 
Yellow 
Base of grain 
Wild type 
Cultivated t3^e 
Shattering 
Shatters 
Does not shatter 
Awns 
Heavy, twisted and geniculate 
None or an occasional awn on 
awns on both upper and lower 
the lower grain. None on the 
grains of a spikelet 
upper 
Pubescence 
Thick pubescence on lateral and 
None or occasionally 1 or 2 hairs 
Base of grain 
dorsal sides of callus on both 
at the sides of the base of the 
grains 
lower grain 
Back of grain 
Heavy pubescence on the back of 
None 
both grains 
Pedicel 
Heavy pubescence on both grains 
None 
