52 
THE AMERICAN BOTANIST 
favorite method. She returns to it again in the locust family 
wherein the ovary is made to serve as a wing for not one, 
but many seeds. If we open a locust pod just before maturity, 
we may wonder why the seeds cling so tenaciously to the pod. 
The seed stalk seems out of all proportion to the needs of the 
seed. But the use of all this is found when the pods ripen. 
At maturity they split open like the pods of the common bean, 
but the locust bean does not drop out of the pod as common 
beans do. There the two halves of the pod hang on the tree 
with their seeds clinging fast, until a gust of 
wind carries pod and all away turning it over and 
over as it goes. Whether the seeds eventually drop 
off here and there I have never been able to discover. Many 
of the pods hang on the tree until the snows have fallen 
and then falling on the snow crust may be blown for long 
distances. The locust, however, does not always grow where 
winter snows are deep, and this trip over the snow was ap- 
parently not planned for when the means of transportation 
were evolved. It may be questioned whether in the making 
of locust-pods, evolution has been influenced much by the use- 
fulness of the pod in distributing the seeds. The long twisted 
pods of the honey locust are too heavy to be whirled away by 
the wind, but they may be rolled over and over after they have 
reached the earth. But the coffee tree with pods thick and 
woody and seeds like bullets firmly attached, though built 
on the plan of the locust pod was plainly never meant for wind 
distribution. 
Still more curious is the fruit of Sterculia platanifolia, 
which Mrs. Bradshaw has recently sent me from California. 
This produces clusters of ovate ovaries in which are borne two 
or three seeds as large as peas. When ripe the ovary splits 
down on the side upon which the seeds are located dividing 
the seeds so that there are one or two on each edge and forming 
a shell-like structure like the vanes of an anemometer. In a 
