LEAVES <: 31 
of the same breadth throughout almost its entire length, as in 
grasses ; or such a leaf may terminate in a sharp point like a’ 
needle, as in Scotch fir. It may be broadest in the middle, 
tapering gradually towards both base and apex, as in wall- 
flower ; or its lower half may be broadest, as in lilac; or again, 
it may be broadest at its apex, as in daisy.. Sometimes the 
blade of the leaf is hollowed out at its base into two rounded 
lobes, whilst the apex is pointed; the leaf is then heart- 
shaped. The opposite of this is seen in the leaflet of the 
wood-sorrel, where the base is pointed and the apex lobe-like. 
In ground ivy, the apex is convex and the base concave; the 
leaf is then kidney-shaped. | 
The margin of the blade may be indented, forming fine 
teeth pointing towards the apex it is then said to be serrate 
(Lat. serra, a saw); if the teeth are coarser and point 
irregularly, the margin is dentate (Lat. dens, a tooth) ; if the 
indentations are rounded, the margin is crenate (Lat. crena, a 
notch) ; when not indented at all, but lying perfectly flat, the 
margin 1s described as entire. In the beech, the margin bears 
delicate hairs, and is then said to be ciliate (Lat. ciliwm, an 
eyelash). 
Stile una In some leaves, as for instance, a species of 
Compound geranium (Geranium molle), the blade of the leat 
HenveS 35 not cub up at all; im others, as the oak, it is 
only slightly indented ; whilst in some others, as certain of the 
geraniums, it is very much cut up. When the incisions reach 
to the midrib, the leaf is described as compound; when the 
incisions do not reach the midrib, the leaf is still simple, 
but if cut up it is described as simple divided ee + 
Fig. 31). 
Compound leaves consist of distinct leaflets, borne by a 
common petiole; they are either pinnate or. digitate 
(Fig. 29). A compound leaf must be carefully distinguished 
from a stem, bearing leaves; unlike the stem, it has no grow- — 
lng point; its growth is, therefore, limited. It has no buds 
in the axils of the leaflets. 
It is interesting to notice that leaves in water are often 
