SPIKELETS AND GLUMES II 
‘of the upper and lower ; similarly the palea is not exactly on the 
same plane as the following glume. And here we must explain an 
unfortunate variance in terminology; some botanists call the 
flowering glume a palea, and then speak of the upper and lower 
palez, which the student will bear in mind when consulting the 
descriptive works of different authors. 
A spikelet may contain one or any number of flowers; that taken 
by way of illustration is four-flowered. One-flowered spikelets are 
very common, ¢.g. in the tribes Agrostidee and Panicea. The 
terms empty and flowering glumes are employed in their literal 
sense; some glumes are, strictly 
speaking, neither empty nor flower- 
ing, as they have a palea in their 
axil, but no flower; these abortive 
glumes occur commonly in the Pan- 
tcace@. As the flower is solitary in 
the axil of its glume, it is obvious 
that the number of flowering glumes 
in any spikelet always corresponds 
to the number of flowers. Cases 
where there are no empty glumes 
at the base of the spikelet are very 
exceptional ; but we have two British 
examples in Mardus and Leersta, 
while in Lo/zum we have an instance 
of only one empty basal glume. On 
the other hand, spikelets often con- 
tain more than two empty glumes, 
and these additional ones are situ- 
ated either immediately above the 
two basal glumes or at the apex of 
the spikelet. For example, in Aa- 
thoxanthum odoratum (fig. 13), the 
third and fourth glumes are empty 
as well as the first and second; in ™™, 
the many-flowered spikelets of the | Fic. 7—Poa pratensis: panicle to 
ets the left, enlarged spikelet above; 
Poaceg it is nearly always the upper- below, flowering glume, palea and 
most or terminal glume thatis empty flower, more enlarged. 
or abortive; in the Panzcacee the 
third glume is usually abortive. The additional empty glume, 
whether in the upper or lower part of the spikelet, is often rudi- 
mentary, or merely represented by a stalk or pedicel. All such 
variations in the structure of the spikelet are important in classifi- 
cation, and the student will require to carefully observe them. 
Sometimes there is a tuft of hairs at the base of each flowering 
glume, on the rachilla; when these hairs are tangled, as in the 
genus Poa, the glumes are said to be webbed. 
The glumes are more or less boat-shaped, thin but firm in 
texture, green, or tinged with brown or purple. They are very 
yarjously modified, and afford valuable characters for determining 
