124 DISARTICULATION OF “SEED” [CH. 
In most of our grasses the caryopsis comes away 
trapped between its two palez, and the latter bring away 
with them the small piece of the axis of the spikelet on 
which they stand: this bit of axis—the rachilla—often 
affords valuable characters in 
diagnosis. (Fig. 41.) It is the 
pair of pales enclosing their 
caryopsis which goes by the 
name of “seed” in most of our 
(Fig. 40.) 
In a few cases, however, e.g. 
grasses. 
Panicum, the spikelet comes 
away as a whole, so that here 
the “seed” consists of the 
glumes, enclosing one, two or 
more pairs of paleze with their 
contained caryopses. 
Even among our native 
grasses, however, cases occur 
where the separation takes 
place below some of the 
glumes, and so the “seed,” as 
met with in samples, consists 
of glumes as well as enclosed 
palez and caryopsis—e.g. An- 
thozanthum, Alopecurus, &c.— 
and some care 1s necessary 1 
Fig. 41. Diagram of a spikelet 
of a grass—e.g. Festuca— 
comprising six matured 
flowers and their pales, 
embraced by the two 
glumes (g!g") at the mo- 
ment of disarticulation as 
the fruits ripen. The small 
piece of axis (a) left attach- 
ed to each segment is the 
rachilla R. At p? the tip of 
the inner palea is visible 
protruding from the outer 
one p!: in the rest it is still 
enclosed in the latter. 
examining grass “seed ” in these circumstances (see p. 134). 
Interesting biological adaptations are met with in the 
cc 
distribution of grass “seeds.” 
The very small and light 
