102 CLASS-BOOK OF BOTANY. 
has an awn or bristle springing from the middle of the 
back and projecting out of the spikelet; this is probably 
only a much-produced midrib. The narrow, erect inner 
scale-leaf is the pale* or palea. The flower itself hag an 
extremely rudimentary perianth, con- 
sisting of two minute scales called 
lodicules,{ 3 stamens with dorsifixed 
versatile anthers, 
and a 1-celled ovary 
containing a single 
ovule and bearing 2 
beautifully plumose 
stigmas. 
As the ovaryripens 
the flowering-clume 
and pale harden con- 
siderably, and the 
former closes firml 
round the fruit. This 
fruit, which is popu- 
Fig. 205. Flower of Oat, Fig. 206. Caryopsis -larly considered to 
with the flowering of Oat, in longi- be the seed only, is 
She 
tudinal section : 
glume removed (mag.). * a kind of achene 
bale pelea: lod, lodi- Guest om“ technically known as 
a caryopsis.! Its 
pericarp is so thin as to be almost imperceptible, and it is 
closely adherent to and amalgamated with the almost equally 
imperceptible testa. ‘The mass of the seed consists of some- 
what hard floury endosperm, on the outside of the base of 
which the embryo is attached. This shows one well-developed 
cotyledon, a plumule, and a radicle. Ifthe grains be soaked 
for a few hours and allowed to germinate, it will be seen that 
the radicte does not elongate into a tap-root, as that of the 
bean does, but that several root-fibres spring from it, each 
surrounded at its base by a small sheath. 
The structure of this sheath should be carefully compared 
with that of a Carex, as the differences are very considerable. 
There are very many kinds of grasses in New Zealand, 
showing considerable diversities of structure, but, in addition 
to the Oat, the most readily studied are the larger-flowered 
kinds, like Wheat and Barley. In all the species found here 
the differences are in details only, not in essential features. 
In Wheat (Triticum sativum) the spikelets are arranged in 
a compound spike. The empty glumes are rather short and 
* Lat. palea, chaff. 
t Lat. lodicula, a small coverlet. 
+ From two Greek words signifying that it resembles a nut. 
