GROSS ANATOMY OF FLOWERING PLANTS. Xix 
wedge-shaped (cuneiform) leaf. In some cases a point or bristle 
grows from the obtuse apex; such are said to be mucronate. 
The extremity when indented is notched or emarginate; when 
this is slight it is retuse; when so deep from the apex as to appear 
cleft the leaf is éifid. A common form of emarginate apex is seen 
in the obcordate (i.c., inversely heart-shaped) leaf, while the emar- 
ginate base is found in the cordate (i.c., heart-shaped) leaf. The 
notch in the base of a leaf is also known as a sinus. 
Margin of the Blade.—When the growth of the leaf has been 
uniform throughout, its margin is an even and continuous line, 
and the blade is said to be entire. More commonly there are 
inequalities in the growth; when thesz are rounded and not great 
the margin may be wavy, or if somewhat more, sinuate, which 
A 
Fie XVI.—Diagram showing the principal forms of margin. 
readily passes into the lobed form, with the projections (lobes) and 
the indentations (sinuses) both rounded. (Fig. XVI.) 
In some cases the projections alone are rounded, the sinuses 
being narrow as if cut. When such projections are small the 
blade is said to be crenate (scalloped); when they are large, cleft- 
lobed, or cleft. (Fig. XVI.) 
When the projections are pointed and small the blade is said to 
be serrated (saw-toothed); when larger and standing out from the 
margin, dentate (toothed); when still larger, incised. (Fig. XVI.) 
When the projections are hardened and sharp-pointed the leaf is 
spiny. 
Venation of the Blade.—The framework of fibro-vascular 
bundles (veins) running through the leaf always conforms to the 
