26 CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. 
be expected, but an examination of the separate families indicates 
that this agreement is accidental, for of the four families one is above 
the expected number by nearly five times the probable error and two 
are below by more than three times the probable error. 
TABLE I1.—Proportion of siveet, wary, and horny seeds of maize compared with 
the expected ratios. 
Family. | 
Descriptive data. Fr | Total. 
Dh221. pDh29. | Dh2i6. Dh207. 
| 
IN CIDer ONCATS A a5 ee ee 12 14 17 12 55 
Number of seeds.........-.--..-- 6, 033 5, 769 6, 413 3,917 22,132 
Sweet seeds: 
INTUN Dee ee ee eee 1,399 1,358 1,720 986 5, 463 
Expected number.....-.--.-... 1,5084+22.7 | 1,4424+22.2 | 1,603425. 4 979+18. 3 5, 533+ 43. 4 
IDYeyrateii(0) ah Spe een ee —109 —84 +117 oA —790 
Deviation divided by proba- 
InlcierlOlaess a ee eae 4.8 3.8 4.6 04 1.6 
IReneen icaers cee ae 23.2 23.5 26.8 25.1 24.7 
Waxy seeds: 
INTint Dei es teeee eee e eee ae 1,085 1,059 1,182 665 3, 941 
Expected number. -........- 1,131+20.4 1,0824+20.0} 1,202+21.1 734411.5 4,149439.1 
DWEViIa ONE s ans eer —46 —23 —70 — —208 
Deviation divided by proba- 
Dlelerrores: sate as. ee ee | 2a8 1.1 Sha) 6.0 Das 
Bomeehh ose 2g fe | 18.0 18.4 7 17.0 17.8 
Horny seeds: | 
NGG Dera se ee eee 3,549 3; 002 3, 561 2, 266 12, 728 
Expected number........... | 3,394+25.9 | 3,245425.3 | 3,608426.8 | 2,2044+20.9 | 12,4504 49.6 
Deviation...) te | +155 +107 17 +62 +278 
Deviation divided by proba- | | 
DIGLe role eee ee ae 6.0 4.2 | 1.8 | 3.0 5.6 
IROWMGON Ts sas. sae oscoee eee 38. 8 Do. 1 | 50. 6_| 57.8 | 57.5 
| | 
CONCLUSIONS. 
The general classification of maize varieties is based on the char- 
acters of the seed. Varieties with horny, soft, and sweet endosperm 
have been recognized since early colonial times, and these three types 
represent the only forms in which the endosperm of maize was 
known to exist until the discovery of waxy endosperm in a variety 
of maize introduced from China in 1908. Investigations of the 
heredity of this new type of endosperm show that when the Chinese 
variety is crossed with sweet varieties seeds are produced which, 
unlike either parent, have a horny endosperm. Although this 
synthetic horny endosperm is indistinguishable from that of ordinary 
field varieties, it behaves in an entirely different manner in the 
following generation. 
All of the plants grown from these hybrid seeds produced ears 
with horny, sweet, and waxy seeds. The proportion in which the 
three classes occurred approximated nine horny, four sweet, and 
three waxy, a ratio indicating that the sweet and waxy characters 
are the result of independent factors and that one out of every four 
sweet seeds, though indistinguishable from ordinary sweet seeds in 
the first generation, represents a new type of sweet corn. Experi- 
[Cir. 120] 
