164 MODIFICATIONS OF THE MARGINS OF LEAVES, 
all point to the apex, the leaf is serrate (figs. 314 and 348), as in 
the common Dead-nettle ; or, if similar teeth point towards the 
base, the leaf is described as retroserrate ; if these teeth are . 
themselves serrate, itis biserrate (figs. 321, b, and 337), as in the 
Elm, and Nettle-leaved Bell-flower; or when the margins are 
minutely serrate they are termed serrulate, as in Barosma serra- 
Fic. 321. 
a b c 
Fig. 321. Diagram of the margins of leaves. a. Bicrenate, 6b, Biserrate. 
c. Duplicato-dentate. 
tifolia. When the teeth are sharp, but do not point in any 
particular direction, and are separated by concavities, the leaf 
is dentate or toothed (figs. 310 and 343), as in the Melon, and 
the lower leaves of the Corn Bluebottle ; or when the teeth are 
themselves divided in a similar manner, it is duplicato-dentate 
(fig. 321, c). When the teeth are rounded (figs. 319 and 349) 
the leaf is crenate, asin the Horseradish, and Ground Ivy ; or if 
these teeth are themselves crenate it is bicrenate (fig. 321, a) ; or 
when the leaf is minutely crenate it is said to be crenulated. 
When the margins present alternately deep concavities and con- 
vexities it is sinuated, as in some Oaks (fig. 322). This kind 
of leaf is sometimes placed under the head of Incision ; it may 
Fic. 322: Fig. ozas 
Qy 
Fig. 322, Sinuated leaf of the Oak.——Fig. 323. Spiny leaf of the Holly (Jlex 
Aquifolium), with wavy margins. 
be regarded as an intermediate condition between a toothed leaf 
and one that is pinnatifid (fig. 313). When the margins are slightly 
sinuous or wavy, as in the Holly (jig. 323), they are said to be 
wavy or undulated ; or when the margins are very irregular, 
being twisted and curled, as in the Garden Endive, Curled 
