1879. | in Natural Selection in Plants. 415 
advances, it will be found that the arrows (ovaries) in these little 
bundles, or quivers, if it be allowable to so natne them, exhibit a 
tendency to separate from the central stalk or axis of the recepta- 
cle, first curling upwards and finally falling off, or are blown out 
and distributed by the wind. 
s soon as the ovaries are detached as above, their styles com- 
mence twisting (see Figs. 5, 6 and 7), and the delicate threads, as 
seen upon and along the slender shaft or style, are consequently 
thrown out at increased angle (sometimes at a nearly right angle), 
so that the entire ovary now presents somewhat the appearance 
of the skeleton or frame, as it were, of a parachute, which after a 
breeze has passed and the air is calm, causes it to descend verti- 
cally, barb downward, so that the tip first touches the ground ;- 
the end of the tip is also barbed, so that if the soil at the spot 
where it alights is at all loose, it holds on. If the weather is dry 
the style or awn becomes still dryer, which causes it to twist still 
more, and the torsion caused by increased desiccation, turns it 
deeper and deeper; while if the atmosphere becomes damp or a 
rain occurs sufficient to moisten the slender style, though but 
little moisture is required to relax the torsion, the bite or grip 
previously made is not lost, because with the softening of the 
style the barb or ovary is not twisted out; whatever hold has 
been gained is retained, and the torsion renewed with recurring 
desiccation, and so the process of planting goes on. 
The small bristles on the surface of the ovary or sheath are set 
obliquely upwards to the axial length and assist in the process of 
planting. It will be seen that every alternation of atmospheric 
conditions, characterized by positive moisture or dryness, assists 
in the operation? 
The luxuriant growth of the cultivated geraniums in California 
is well known. In and around Berkeley nearly every yard has 
many plants of one or more varieties. On my premises are 
numerous vigorous plants of large size and of many varieties, 
including Pelargoniums. 
1 This is easily illustrated by the following simple experiment: Take a tumbler 
and fill it with sand; select specimens of the gynæcia or receptacles which are 
beginning to turn brown or approaching ripeness, that is while the seeds complete 
its tip is fairly set; it will soon be noticed as the ripening progresses, or as the awn 
or shaft begins to dry that it also begins to curl or twist, and that in curling it buries 
the barbed ovary deeper and deeper, as turning a corkscrew carries the same deeper 
and deeper into a cork. 
