10 STRUCTURE 
divided and sub-divided, forming the graceful airy panicle so char- 
acteristic of grasses (fig. 6). The ultimate branches of the panicle 
are of course the pedicels of the spikelets, and the number of spike- 
lets contained in this paniculate form of inflorescence is often 
immense. In the raceme, an intermediate form of inflorescence, 
each spikelet has its pedicel inserted directly upon the rachis. The 
panicle may be pyramidal (figs. 7, 8, 37), or oblong (fig. 14), or 
cylindric (fig. 18), lax (figs. 19-26), or dense (figs. 18-21), spread- 
ing in all directions, or one-sided (unilateral). In some cases the 
branches of the rachis are so short that the inflorescence resembles 
a spike (figs. 13, 16); such a panicle is termed spikelike. Especi- 
ally is thisso with the genera PAleum and Alopecurus (figs. 18, 36,) 
which have such a dense contracted panicle that the extremely 
short branches are quite con- 
cealed. The inflorescence in 
its rudimentary state—a clus- 
ter of papilla, each a rudi- 
mentary spikelet — will be 
found, some weeks before the 
flowering season, within the 
leafy shoots, close to their 
base, and immediately above 
the uppermost node. 
The spikelets vary in shape 
from orbicular (nearly round) 
to narrowly-elliptical and tap- 
ering (lanceolate), or cylindri- 
cal; most commonly they are 
egg-shaped (ovate). They are 
often laterally compressed, z.e. 
flattened at the sides of the 
glumes, but in most Pazicacea, 
they are somewhat dorsally 
LAr adi F fants a panies & compressed. When of varying 
alkeles closed csikelet open, showing the diameter, but not compressed, 
so that a cross-section made 
at any point is round, they are described as terete. Let us now 
dissect a spikelet like that in fig. 7 (upper figure). The glumes, 
six represented in this figure, are sessile on a slender axis (rachilla) 
which is concealed, and are arranged distichously, z.2. in two 
opposite rows, and alternately in harmony with the phyllotaxis of 
the leaves of the stem. The pair of apparently opposite glumes at 
the base of the spikelet are empty ; each of the others, called 
flowering glumes in contradistinction to the empty ones, bears in 
its axil, and envelops or embraces at its edges, another bract termed 
the palea (lower figure). Within the flowering glume and palea, 
and partly concealed by these, is the solitary sessile flower which 
we shall describe presently. None of these bracts form any part 
of what are technically known as floral envelopes. As the two 
empty glumes are inserted one slightly above the other, we speak 
