572 How the Pitcher Plant got its Leaves. [June, 
over the open, honeyless pitcher of S. purpurea is at once mani- 
fest. But a still further advance is found in Darlingtonia, 
the third genus of the order and a native of California. In this 
the leaves are very long, stand upright and have a peculiar 
twist not found in any other species (Fig. 6). The hood, in 
addition, forms a vaulted arch, mottled with spots and reticu- 
lations. The only entrance to the leaf is from below, and on 
each side of this entrance is a long appendage, the whole 
likened to a fish tail. The inside of this secretes honey and is 
covered with hairs. The interior of the pitcher is lined with vast 
numbers of hairs, which become longer and more bristly toward 
the bottom (Fig. 7). A secretion is found here that has the 
power of decomposing the bodies of the insects which have been 
entrapped. On the outside, running along the wing, from the 
ground to the orifice, is a honey pathway which lures creeping 
insects to their destruction. The wings or fish-tail, at the top of 
the pitcher, attract flying ones. 
In these species of plants there is a regular gradation from the 
simple to the complex. From the Heliamphora with its open 
pitcher and small hood, to the Sarracenia purpurea with upright, 
less open pitcher and larger hood; thence to the S. variolaris 
through several stages of less complexity, with its almost closed 
pitcher, power of secfeting honey and digestive fluid; then to 
the more remarkable Darlingtonia, with its large twisted leaves, 
with vaulted hoods and fish-tail appendages, decomposing fluid 
and honey-secreting apparatus. Scarcely any of the steps showing 
the progress are needed to complete the line of development. It 
can be traced directly from Heliamphora to Darlingtonia, and it 
is only necessary to have an ancestral form from which to start 
to have a complete pedigree. 
It seems probable that the water-lily family and the pitcher- 
plant family had a single ancestor in common. This ancestor 
was aquatic, or at least an inhabitant of swampy places. It had 
_ small, probably peltate, perhaps reniform leaves, and these had 
- hollow petioles. The inner space was lined with hairs as are now 
the inner surfaces of the stems of Nymphza and its allies; it had 
a four or five parted flower, with many stamens and a broad 
ERS 
= From such an ancestor came’ two or three branches. One of 
= these developed into plants having an aquatic habit, large leaves 
x i 
