52 
carrying with it a fruiting glume (fig. 34). 
CLASSIFICATION 
The pair of empty 
glumes at the base of the spikelet remain attached to the pedicel ; 
Fic. 34. — A fruiting 
glume of Dactylis glom- 
erata: ya piece (inter- 
node) of the rachilla ; the 
glume next above (in the 
spikelet) was seated on 
the top of it; g margin 
of glume inflected over /, 
the palea ; grain conceal- 
ed between glume and 
palea. 
this is shown in fig. 35, which compare with 
fig. 14, showing the spikelets of the same plant 
when in flower. The articulation is not always 
evident at time of flowering, but in the fruiting 
season it can be detected by the facility with 
which the fruiting glume can be broken off. 
We thus see that in the Pandcacee the empty 
glumes are deciduous; in the Poacee per- 
sistent in fruit. In the case of 1-flowered 
spikelets of Poacee, the rachilla is that minute 
fragment, by some termed the callus, embraced 
by the base of the flowering glume, and the 
joint or articulation is between this fragment 
and the pedicel, z.e. above the empty glumes. 
With regard to the second character on 
which the primary division is based, in the 
Panicacee the imperfect (staminate) flower, or 
additional empty or rudimentary glume, is 
always situated below the bisexual flower ; in 
other words, the imperfection is near the base 
of the spikelet. There are never more than 
four glumes, the two lowest of which are 
empty ; the next, ze. the third one, may also 
be empty, or it may enclose a palea or a 
male flower; the fourth, ze. the uppermost 
glume, encloses the bisexual flower. 
In the Poacez, on the other hand, the im- 
perfection is in the upper part of the spikelet ; the male flower 
or‘ additional empty glume or rudiment (when present) being at 
Fic. 35.—Portion of panicle 
of Bromus mollis, after shed- 
ding of fruit, showing the per- 
sistent empty glumes. 
the apex of the spikelet, z.e. terminal ; hence 
it is sometimes spoken of as the produced 
rachilla. The spikelets may contain one 
or any number of bisexual flowers, and 
have accordingly three or more glumes ; 
some species of Lragrostis have as many 
as 50 flowering glumes in a spikelet. 
Series A. PANICACEA:. Spikelets 
articulated to the pedicel (below the empty 
glumes), containing one bisexual flower, 
with a male flower or third empty glume 
or rudiment beneath. Only two tribes are 
represented in Britain, viz. :— 
Tribe PANICE. The principal character 
is the hardening of the flowering glume 
around the fruit ; flowering glume awnless. 
There are three British genera : 
Genus I. 
Panicum. 
Rachis compound, spikes often spreading 
like fingers from a common insertion (digitate), or panicle lobed ; 
