+ GENERAL CHARACTERISTICS [CH. 
whether in flower or not, forced itself on the attention, 
and although a botanist naturally turns to a good Flora 
when he has the grass in flower, as the best and quickest 
way of ascertaining the species, it soon became evident 
that much may be done by the study of the leaves and 
vegetative parts of most grasses. Indeed some are recog- 
nisable at a glance by certain characters well known to 
continental observers: in the case of others the matter 
is more difficult, and perhaps with a few it is impossible 
to be certain of the species from such characters only. 
Nevertheless, while the best means for the deter- 
mination of species are always in the floral characters so 
well worked up in the Floras of Hooker, Bentham and 
others, there is unquestionably much value in the 
characters of the vegetative organs also, as the works 
of Jessen, Lund, Stebler, Vesque and others abroad, and 
Sinclair, Parnell, Sowerby and others in this country 
attest. 
Almost the only plants confounded with true grasses 
by the ordinary observer are the sedges and a few rushes. 
Apart from the very different floral structures, there are 
two or three easily discoverable marks for distinguishing 
all our grasses from other plants (Fig. 1). The first 1s 
their leaves are arranged in two rows, alternately, up the 
stems; and the second that their stems are circular or 
flattened in section, or if of some other shape they are 
never triangular and solid? (Figs. 6 and 7). Moreover the 
leaves are always of some elongated shape, and without 
1 Some foreign grasses (Andropogon, Panicum, &c.) have solid stems, 
and in Psamma and some others the lower parts may be solid. 
