138 THE VEGETABLE WORLD. 
as in the Blumenbachia insignis. Sometimes they take the form 
of a spoon, as in the Dielytra spectabilis (Fig. 166); some- 
times they show two lips, as in the Fennel-flower (Fig. 167) ; 
sometimes they are elongated like a horn, as in the Columbine 
(Fig. 168) ; sometimes they are helmet-shaped, as in the Aconite 
(Fig. 169). 
Petals, like leaves, are either entire or indented. They pre- 
sent, like them, a sort of skeleton, if one may give that name to 
vascular and slender ramifications, which can only be perceived 
clearly in some cases by placing the petal between the eye and the 
light, so as to look at them as at a transparency. 
The veins determine the shape assumed by the petal. Figs. 170, 
171, and 172 give an idea of the three principal forms for the 
i\ i 
ey 
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t 
| 
Fig. 170—Petal of Wallflower. Fig, 171.—Petal of Winter Fig. 172.—Cerastium 
Hellebore, precox. 
distribution of the veins. We know that in the Wallflower (Fig: 
170) the petal is elongated at its lower part by a slender portion 
called the claw (wnguis), the larger part of the petal taking, in this 
latter case, the name of the limb. The petals of the Cerastwm 
precox (Fig. 172) and Winter Hellebore (Fig. 171) have no claw, 
and, as we see, one limb only. 
The number of petals in a corolla vary much; they are some- 
times very numerous, and are then arranged in a spiral form ; ut 
they are oftener few in number, and are then arranged in one whorl. 
In the Cactus the petals are extremely numerous, and arranged in 
a spiral, continuous with that of the sepals. In the Geranium 
(Fig. 173), Violet, and Gilliflower (Fig. 174), there are only five 
petals arranged in a whorl. 
