THE REST-PERIOD OF SEEDS 433 



It can be easily demonstrated that ripe moist acorns are 

 able to proceed at once with germination if placed under 

 conditions inhibiting the drying of the fruit. Thus on 

 September 17, 1908, I collected some ripe acorns and placed 

 them at once in damp moss in a warm cupboard. They were 

 still biologically connected with the cupules, and their shells, 

 though beginning to brown, were still thick and moist. 

 Within eight days I found some of them germinating norrrially, 

 and one of them when planted grew healthily under protection 

 during the winter. (Whilst preparing this chapter (September 

 191 1) I repeated this experiment with green ripe acorns show- 

 ing no signs of drying, and possessing, as in the first case, entire 

 shells. In five days half of them were splitting their shells, 

 and several of these were protruding the radicle.) 



Every autumn I noticed a small but variable number of 

 ripe acorns showing signs of germination on the trees in the 

 splitting of their shells and in the slight protrusion of the 

 radicle. The growing seed had burst the fruit-case, and in 

 many cases it was evident that the seed was larger than its 

 shell. This was recorded at the end of September 1908, in 

 the first half of October 1909, in the middle of October 19 10, 

 and in the second week of September 1 9 1 1 . A number of 

 the split nuts placed at once in wet moss in two different 

 autumns were found in four or five days well advanced in the 

 germinating process. When the acorn begins to split at its 

 sides it is full-sized, moist, and green, and is still vitally con- 

 nected with the cupule. Usually the protrusion of the radicle 

 is not great on the tree ; but I can recall a case where its 

 growth was considerable, and where the inner surfaces of the 

 cotyledons were turning green whilst the fruit was still 

 attached. 



This attempt at germination on the tree soon brings about The fate of 



the fall of the nut. The shell browns rapidly as it dries, and that germin- 



the fruit is soon vitally disconnected from the cupule. Generally ^*|^°" *^ 



the fallen acorn dies ; but it must frequently happen in moist 



mild weather that it continues the growth commenced on the 



28 



