THE VEGETATIVE ORGANS COMPARED 341 
(Fig. 291). The relation of the very narrow mouse-tail leaf 
to one of the marsh-marigold type may be understood by 
supposing the nerves to be reduced to a single rib. A leaf 
in which the framework consists of only one or two ribs, 
may be termed costate.!_ The simple leaf of the silky clematis 
may be likened to a less narrowed marsh-marigold leaf in 
which, however, the ribs are reduced to one midrib from 
which veins are given off on either side. Or, better, we may 
Fig. 296.—Staminodes. A, Anemone Pulsatilla. B, Ranunculus acris, view 
from above. C, same, cut vertically; the shaded area (S) indicating the 
surface secreting nectar. D, Nigella damescena, view from above. 
E, same, cut vertically; secreting surfaces (S) shown as before. All 
variously enlarged. (Redrawn from Prantl.) 
Fic. 297.—Ovyary of an anemony, opened to show the two pairs of rudi- 
mentary ovules above the single normal one, enlarged. (Baillon.) 
view it as an elongated leaf in which the framework was at 
first divided palmately into three branches, the middle one 
of which again divided similarly, and this method of branch- 
ing continued during the elongation of the blade. However 
we may view the nervation, such a leaf in which a single 
midrib, or direct continuation of the petiole, gives off several 
or many lateral branches, is distinguished as pinnately nerved. 
The leaves of the pasque-flower are described as pinnately 
compound or pinnate.2. The leaflets of the Christmas rose are 
pinnately nerved, the leaf as a whole being palmate or pedate. 
1 Cos’-tate < L. costa, a rib. 
2 Pin’-nate < L. pinna, a feather, because the veins arise from the 
midrib as do the barbs of a feather from its shaft. 
