430 STUDIES IN SEEDS AND FRUITS 



size being principally due to the growth of the endosperm. 

 The small embryos also added to their bulk, but at a rate not 

 much faster than the seed. They displayed but little evidence 

 of having grown at the expense of the food-reserve, and 

 remained white, with their cotyledons appressed. From the 

 end of January up to the middle of March there was a sus- 

 pension of the growth of the fruit, seed, and embryo ; and 

 here the observations for that season ended, the embryo 

 remaining in the same colourless, inert condition. The winter 

 was severe, and I think it very probable that under milder 

 conditions there would not have been this check. 



The latter part of the history of the growth of the embryo 

 in the seed on the plant is supplied by my own observations 

 during four successive springs. Since their general results 

 agree, I have only given in the table those for 1909 and 1910. 

 It is there indicated that after March the embryo grows with 

 arc ' fair rapidity. Taking all the data of the four years, the average 

 growth in the spring would be as follows : By the end of 

 March or the beginning of April the embryo would be about 

 3 millimetres long, or just half the length of the kernel, but 

 remaining white and showing no enlargement of the cotyledons. 

 During the latter part of April and the early part of May most 

 of the berries fall to the ground, their detachment being 

 hastened by wind and rain. The seeds of those that remain 

 usually display embryos 4 or 5 millimetres long, increasing 

 perceptibly at the expense of the albumen and with enlarged 

 green cotyledons. As May advances the embryos attain the 

 length of the kernel (6 to 7 millimetres), some of them 

 becoming even longer, so that they are compelled to accommo- 

 date themselves to the kernel's length by bending, as shown 

 in the figure for May 16. A few seeds will be found 

 germinating within the fruit, which has already begun to 

 shrivel and soon drops off. Whilst the berry is attached to 

 the plant the radicle pierces the seed-coats, but not the pericarp, 

 the hypocotyl becoming bent over the seed inside the fruit. In 

 these germinating seeds the albumen has largely disappeared. 



