from Botanical and Economic Aspects. 229 
that mere lateness of ripening need not indicate a poor or 
primitive fruit. The small amount of the fruit pulp and the 
small size of the seeds in specimen I, are additional proofs 
that this is a primitive form, rather than a degraded one. 
Until better and more conclusive evidence is obtained, we 
may accept the above as probable, and now try to determine 
the cause or causes for the origin of the varieties. It deserves 
to be emphasized, that most of our cultivated plums, and also 
the sand cherry as well as the beach plum, show fruit and 
seed variations exactly along the lines of those now described. 
This might indicate that all of these are comparatively recent 
evolutions from a common stock that acquired these varietal 
variations and then branched off into specific lines of develop- 
ment in stem, leaf and flower, without losing the fruit and 
seed variations already acquired in common. From a primi- 
tive small, hard, semi-succulent, purplish green, late-maturing 
type like No. I, we might have in each of the specific groups 
lines of variation passing from it to greenish purple, to purple, 
purplish blue and blue black. Or again from the same start- 
ing point we might obtain, by predominence of acid cell 
contents, greenish red, red, reddish-yellow, to yellow. 
As to the possible cause for the origin of these varieties, the 
writer has nothing of value to suggest. Some suggestions 
may, however, be offered. Thus when study of all the 
environmental conditions is made, it is seen that these plants 
usually grow where alterations in the relations of sea and land 
are frequent. The varieties of sub-soil also vary considerably, 
and may affect the plants, according to the heaviness or 
porosity of it. The relative amount of the halogen compounds 
in the soil round a plant or plant group, may likewise have 
a determining effect. Exposure to a bright, hot sun, or 
protection in comparative shade may also have been a deter- 
mining factor. A fruitful field for observation and experiment 
is open here as in many other fields, and suggests to us the 
