224 Macfarlaiic — Tlic Beach Plum, Vicivcd 



fruits. These mature from about August lo on to the first week 

 in September. Meanwhile the blue and blue-black, also the 

 yellow varieties are coming forward, and give a succession of 

 fruits from about August i8 to September lo. These again 

 are followed by the small purplish-blue types, which ripen 

 from about September i to 20. Finally, during the latter 

 part of September and on to October i 5, the medium-sized 

 and small greenish-purple varieties ripen. These last seldom 

 seem to attain the consistency — even in October when they 

 fall — that we call ripeness. They are then decidedly firm in the 

 flesh, and abound in tannin and acid constituents. 



(g) Variatiojis in Fr^iit Stones. — Darwin has drawn attention 

 to, and has figured, varieties of the fruit stone of the cultivated 

 plum.^ Though nothing has been observed in the beach plum 

 that would compare with these, the differences are nevertheless 

 suggestive. We may at once compare two rather extreme 

 cases presented under Nos. 7 and 12 of the table. The 

 former are oval, compressed in shape, are slightly rough and 

 have a well-marked ridge that traverses one side and ends in 

 a sHght beak. The color is a dull crimson-red, the weight 

 is .60 gram, and in relation to the pulp the stone is of 

 cling-stone variety. The stones of No. 1 2 are of nearly spheri- 

 cal shape, smooth and have only a faint indication of a ridge 

 The color is a clear liquid yellow, the weight is .28 gm. and 

 the pulp is entirely free from the stone. 



A Comparison of the Beach Plum with the Cultivated 

 Plum and Economic Suggestions Arising Therefrom. 



It seemed advisable during the progress of the present 

 inquiry to institute a comparison between fruits of the beach 

 plum and those of the garden plum. Authorities differ as to 

 the wild parentage of the latter, but most agree that Pninus 



1" Variation of Animals and Plants," Vol. I, p. 366. 



