222 Macfarlanc — The Beach Phtvi, Viezueci 



limited centers of plant distribution, types may originate 

 apparently from no traceable environmental causes, which 

 vary powerfully in the very parts — fruit and stone — that con- 

 tribute to the perpetuation and distribution of the species. 



{c) Fruit Ste and Shape. — The two smallest fruits 

 observed, belonged to plants that differed in nearly every other 

 respect, viz.: Nos. i and 12 of the above table. Both were 

 spherical fruits that had a cross-measurement of 1 1 to 13 mm. 

 Occasionally bushes of type i may be encountered in which the 

 shape tends more toward the spheroid. Intermediate grada- 

 tions can be traced from these to the largest, which was sphe- 

 roidal in shape and measured 21 mm., but the most note- 

 worthy in shape of its fruits was No. 3 of the table. Two 

 bushes were observed, the fruit was oval in outline and 

 measured 12 by 17 mm. The shape and size were surpris- 

 ingly uniform over each plant, and indicated a fixed heredi- 

 tary condition in the plant. 



As in our varieties of the cultivated plum, so in these a 

 pronounced carpellary sutural groove may occur in some, 

 only a faint trace of it in others, while in Nos. 4 and 10 of 

 the table the groove is obliterated. 



((/, c) Fniit Taste ami Consistence. — The numerous varia- 

 tions shown, in both of these respects, by the cultivated 

 plums of our day are well known. Similar variations are seen 

 in the wild beach plum. Average fruits have what might be 

 described as a slightly watery pulp, that is, instead of posses- 

 sing the firm continuous pulp of our best plums, it here con- 

 sists of pulpy tissue filled in between with softer, almost 

 watery material that inclines to drip. This is true of the 

 finest blue-black fruits of large size, such as No. 7 in the 

 table, and even of the small blue-black types. The purplish- 

 red and yellow fruits are of firmer texture, while No. i of the 

 table has a hard, close pulp, that is small in quantity and poor 

 in quality. 



