THE 
AMERICAN NATURALIST. 
VoL. xur. — FULY, 1879. — No. 7. 
FORM OF SEEDS AS A FACTOR IN NATURAL 
SELECTION IN PLANTS 
BY ROBERT E. C. STEARNS. © 
i te present aspect of the fields in the immediate neighbor- 
hood of the south grounds of the University of California, at 
Berkeley, when compared with their general appearance five years 
ago, when the flora of the locality was first noticed by me, exhib- 
its a marked contrast; and though during this time the vary- 
ing character of the vegetation from year to year attracted my 
attention, the altered physiognomy of the fields particularly 
impressed me this past season, and curiosity has led me to seek 
for the causes which have produced what may be regarded as a 
most striking change, 
The complexity of questions of this kind is increased, not only 
through the simpler factors involved, some of which are given 
below, but by the sequence of relationship of such factors to each 
other, which it is difficult to detect. 
The climatology of the seasons during which such changes 
have been progressing ;—the tillage of proximate lands, and the 
introduction of new plants, or of plants new to a locality, through 
this agency or by other artificial means more or less direct, which 
follow the settlement of a region;—other changes which follow 
through neglect of tillage, as where the cultivation of farm- 
ing lands is abandoned, as is generally the case where such lands 
are divided and cut into small parcels for village or town plats or 
lots ;—these are a few of the more conspicuous agencies which 
produce changes of the kind mentioned herein, in the local flora 
of such neighborhoods. Again, the time required for the growth- 
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VOL, XIII,—No, VIL 
