1879. | in Natural Selection in Plants.” 419 
The spikelet as a whole may be regarded as a wonderfully 
ingenious, compound and effective barb, having through the 
angle of its various parts and the length of the awns, all of the 
advantages of the parachute form which Erodium and the culti- 
vated geraniums referred to derive from their twisted styles with 
fine lateral hairs, for floating in the air and for poise in ultimate 
descent. 
The principal advantage which Erodium has over this Hordeum 
is in the hygroscopic torsion of the styles? or awns; this is more 
than balanced by the preponderance of barbs and bristles in Hor- 
deum, all of which are set at some angle outward and upward, 
while the spoon-shaped basal nib, arrow-head or insertion point, 
whichever it may be termed, is perhaps equally well adapted as 
the same part in the carpels of Erodium, for biting and holding 
on; once inserted, every motion it receives, whether from the 
wind or other source only inserts it deeper and deeper, and in 
this the nib or insertion point is assisted by the other parts of the 
spikelet. Another and probably the chief-advantage which the 
barley-grass has over Erodium is in the greater number of seeds 
(three in a spikelet) in a single plant; recurring again to the fact 
that cattle dislike it on account of its wiry, prickly character, 
which gives it almost perfect immunity or protection from their 
proweing, it is easy to perceive why it has become nearly if not 
quite “ master of the situation.” 
To the farmer it is a pest and to the ean a nuisance, as 
the spikelets stick into the trowsers around the foot, working in 
deeper and deeper with every motion, often crawling upwards as 
far as the top of the boot-leg, where if the stocking is long and 
extends above, it catches and follows down into the foot, irri- 
tating the flesh and compelling a halt in order to remove the 
annoyance, 
Under a microscope lens the main barb (insertion point or nib) 
is an interesting and curious object; the unshaded edges (see 
figure) and the ie barbs upon the same are translucent, being 
1¢ A wi ei oat * * * * the A. sterilis of botanists, is cpa agg Ar the 
hygrometric properties of the seed. Two grains usually grow together, they 
have a ines, bent and twisted awn. When the oat is ripe it falls out of its ele 
and in warm weather may be seen rolling snd turning about on its long ungainly 
emain quiet till the acpi falls, or they are moistened by a shower, when they 
rapidly untwist and run about as if anxious to escape from the wet?’ —Baird’s Dict. 
Hist. p. 27. 
ne 
