338 TWENTY-FIFTH ANNIVERSARY REPporT. 
with different seeds but probably designed in all cases to protect the 
inner portions of the seeds from mechanical injury, excess of moist- 
ure and germs of decay. Thus it was found in experiments* at 
this Station that the seed coat evidently retarded germination. This 
is probably due to its keeping out a portion of the water which 
would otherwise be absorbed, the taking up of moisture being the 
first stage of germination. In all cases where this seed coat was 
artificially broken the seeds germinated in less time than similar 
seeds in which the seed coat was intact. A coat of tar or tallow 
increased the length of time necessary for germination. 
In comparing the large with the small seed it is evident that the 
difference in size must be due to one of three causes; either the 
embryo of the one must be larger than that of the other, the en- 
dosperm greater, or both embryo and endosperm may be of an in- | 
creased size in‘the larger seed. It seems probable that this greater 
size, whether it be due to embryo or endosperm, or both, would be 
of advantage to the seedling at least in the early stages of growth. 
Whether this advantage would continue after the plant had formed 
its own leaves and roots is not so apparent. To determine this 
point many tests were made with different kinds of seeds.#? The 
tests were faulty in that the seeds were usually divided into large 
and small by the use of sieves, whereas weight would have been a 
more correct criterion. Of two seeds of different sizes the larger is 
generally the heavier, but this is not invariably the case. At differ- 
ent times seeds of the following plants were divided into two lots 
according to size. The plants were turnip, onion, cabbage, cauli- 
flower, beans, corn, and oats. 
In the turnip the small seed gave a slightly larger root than the 
large seed, the difference being only a fraction of an ounce. With 
the onion there was a slight difference in the crop in favor of the © 
large seed. Of the nine varieties tested, one variety gave bulbs from 
the larger seed more than double those from the smaller seed. If 
this variety had been eliminated from the test the results would 
have been slightly in favor of the small seed. The results from the 
sowing of eleven packets of savoy and twenty-one packets of smooth 
cabbage seed exactly balanced each other, with the savoy the heavier 
heads coming from the small seed, while with the smooth cabbage 
the reverse was the case. In the test of large and small cauliflower 
* Rpt. 3:328 (1884). 
*® Rpt. 1:80 (1882) ; 2:71 (1883). 
bc indices eile 
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