THE NATURAL HISTORY OF BRITISH GRASSES. 27 
smaller than the latter. Again, the outer and inner valve 
may vary in size and shape, and, indeed, present many 
differences which will be explained in simple language in 
the descriptions of species. 
The glumel,—corolla, is subject to like differences in 
form and proportions, facts which can only be well explained 
with a specimen in one’s hand; and it should not be 
forgotten that in grasses we have to deal with plants which, 
though simple in their structure, present such minute 
differences that the eye must become by use accustomed to 
examine and trace them, and as so many characters are 
necessarily derived from such important organs as the 
flowers, which are often small, even a pocket lens will 
frequently be required to assist the ordinary vision.* 
The glumel is often found to be armed by a projecting 
spine or beard; this is of greater or less length, and is 
termed the awn,} and may be well observed in bearded 
wheat and in both wild and cultivated barleys. This organ, 
when long and stiff, and armed as it is sometimes with 
projecting spicule, renders grasses where they occur 
exceedingly objectionable, especially for hay, though the 
grass may be good if kept from flowering by constant 
depasturing ; such are the species of Hordewm (wild barley). 
The fertilizing organs consist of the stamens; which 
possess the following parts :— 
a. The filament, or thread which supports 
6. The anther, or case in which is secreted 
e. The pollen, or fecundating dust. 
The filament, by reason of its length, may cause the 
anther to be exserted or standing out from the flower, or 
from its shortness to be inserted or included in its valves, 
the anther may be varied in its colour as follows :—{ 
* For this purpose a lens of ordinary power will suffice, such as may 
be purchased at the optician’s for about 9d. 
+ The awn, when present, may represent the blade of a leaf, whilst the 
glume and glumel are the representatives of the sheath. 
{ The colour differs much in the same species, some being more liable 
to variation than others. 
