416 -Form of Seeds as a Factor [July, 
The question naturally occurred, why have not these orna- 
mental forms which have the great advantage over their wild 
relatives of the protection and fostering care of man, spread like 
the unprotected Zrodium and divided the field with it or driven it 
out? The seeds are not infertile, for under the shade of the 
sturdy plants which produce them, protected during the hot dry 
summers by the leaves which fall from the parent plant and make 
the thin mulch which covers them, with infrequent and slight 
sprinkling during the long rainless season, hundreds of young 
plants may be seen in the fall which have sprung from the loose 
and slightly moistened soil and acquired their second pair of 
leaves. The carpels are of the same form as those in Erodium ; 
few persons could detect any difference, and the awn or style 
twist in the same way. Upon critical examination, however, it 
was found that the tip (insertion point) of the carpel was covered 
with soft silken hairs instead of rigid bristles, too soft to act as 
barbs, and the insertion point is neither as sharp or stiff nor curved 
the same as in Erodium. 
The seeds of all of these foreign forms which have been exam- 
ined by me in this connection, are apparently dependent for dis- 
tribution chiefly on the winds, for the delicate filaments along the 
style if not longer are more numerous than in Erodium, so that 
when the twist or torsion has occurred, they present a form well 
adapted for distribution by flight. 
Darwin has noticed the advantage which winged seeds have in 
this respect, as well as those plants whose seed cups or receptacles 
have a rough exterior, which get caught in the hair or fleece of 
animals and are thereby transported from place to place. In this 
way also the seeds of the geraniums have some advantage, but as 
compared with those of Erodium, so far as planting by natural 
methods is considered, the advantage is ks eg Se in favor of 
the latter. 
I do not know how it is with the cultivated varieties referred 
to in their native country, neither can I assert how it might be 
with our Erodium forms if transplanted to another region; a dif- 
ferent environment might induce a gradual modification in those — 
peculiarities which in the environment of Berkeley are important 
factors in their propagation and the extension of their geographi- 
cal domain. It is not difficult for a person who is familiar with 
the cultivation of plants, and who has had an experience covering 
