52 CLASS-BOOK OF BOTANY, 
(b.) Of indigenous species there is considerable variety, 
and species of Hydrocotyle* (with simple rounded leaves and 
flowers in simple umbels), Ligusticwm, and Angelica are com- 
mon. The most striking form, however, is the Spear-gragg, 
belonging to the genus Aciphylla. Five species are known in 
New Zealand. In all of them the leaves are once or twice 
pinnate, and the leafiets, together with the involucral bracts, 
are spiny. The umbeis are not flat-topped as in most of the 
cultivated umbellifers, but are crowded into more or less dense 
panicles ; and the flowers are dicecious or polygamous. | 
Fig. 81. Flower of Panax 
arboreum. * 
Fig. 80. Fruit of 
Spear - grass 
(mag.). 
Fig. 79. Part’of ¢ inflorescence Fig. 89. Longitudinal sec- 
of Spear-grass — Aciphylla tion of ovary of Panaz. 
colensot. ; 
Somewhat closely allied to umbelliferous plants are the 
various species of Panax (Grass-tree, New Zealand Gum, &C.). 
They differ not only in their arboreous habit, but in usually 
having more than two cells in their ovary. The fruit does 
not split up into its separate carpels, and remains somewhat 
fleshy when mature. 
STRUCTURE AND. Mopxs oF DEHISCENCE OF THE FRUIT... 
In describing the buttercup and all the plants subsequently 
examined we have spoken of the carpels as modified leaves, but 
no attempt has yet been made to show how this leaf-struc- 
ture can be made out in those ovaries which are composed of 
several such carpels. Let us again examine the pod (legume) 
of a pea, which exhibits the simplest form, and is composed of 
SR ine Fite ae eS Se 
* See fig. 173, p. 88. . 
