w-shaped_, where such ears are acute and turned
downwards, while the main body of the blade tapers upwards to a point,
as in the common Sagittaria or Arrow-head, and in the Arrow-leaved
Polygonum (Fig. 125).

_Hastate_, or _Halberd-shaped_, when such lobes at the base point
outwards, giving the shape of the halberd of the olden time, as in
another Polygonum (Fig. 127).

[Illustration: Fig. 128-132. Various forms of radiate-veined leaves.]

_Peltate_, or _Shield-shaped_ (Fig. 132), is the name applied to a
curious modification of the leaf, commonly of a rounded form, where the
footstalk is attached to the lower surface, instead of the base, and
therefore is naturally likened to a shield borne by the outstretched
arm. The common Watershield, the Nelumbium, and the White Water-lily,
and also the Mandrake, exhibit this sort of leaf. On comparing the
shield-shaped leaf of the common Marsh Pennywort (Fig. 132) with that of
another common species (Fig. 130), it is at once seen that a
shield-shaped leaf is like a kidney-shaped (Fig. 130, 131) or other
rounded leaf, with the margins at the base brought together and united.

137. =As to the Apex=, the following terms express the principal
variations:--

_Acuminate_, _Pointed_, or _Taper-pointed_, when the summit is more or
less prolonged into a narrowed or tapering point; as in Fig. 133.

_Acute_, ending in an acute angle or not prolonged point; Fig. 134.

_Obtuse_, with a blunt or rounded apex; as in Fig. 135, etc.

_Truncate_, with the end as if cut off square; as in Fig. 136.

_Retuse_, with rounded summit slightly indented, forming a very shallow
notch, as in Fig. 137.

_Emarginate_, or _Notched_, indented at the end more decidedly; as in
Fig. 138.

_Obcordate_, that is, inversely heart-shaped, where an obovate leaf is
more deeply notched at the end (Fig. 139), as in White Clover and
Wood-sorrel; so as to resemble a cordate leaf inverted.

_Cuspidate_, tipped with a sharp and rigid point; as in Fig. 140.

_Mucronate_, abruptly tipped with a small and short point, like a mere
projection of the midrib; as in Fig. 141.

_Aristate_, _Awn-pointed_, and _Bristle-pointed_, are terms used when
this mucronate point is extended into a longer bristle-form or slender
appendage.

The first six of these terms can be applied to the lower as well as to
the upper end of a leaf or other organ. The others belong to the apex
only.

[Illustration: Fig. 133-141. Forms of the ap