124 NYMPHA‘A’ FLAVA,— AUDUBON’S YELLOW WATER-LILY. 
Lily;” the close student of plants as well as the more acute 
botanist will be pleased with the study of the growth and develop- 
ment of the plant itself, The “common white water-lily” has a 
taick creeping rhizome or main stem,—in this species the root- 
stock is erect (Fig. 3). This seems to be in the main made up 
of imperfectly developed leaves, just as the scales of a true lily 
bulb are formed. During the next year roots come out from 
these scales, and, when they die, as they do in the following fall, 
they leave each scale pitted as seen in our enlarged drawing 
(Fig. 7). From some of these, however, one thready point, at 
first as like a root as the rest, proceeds onward, and finally 
makes a young plant capable of flowering in the autumn of the 
same season (Fig. 4). From the study of this thread in its 
early life we may learn how nearly allied in their nature may be 
a root and the runner, as the thread is called in popular language. 
This young plant has a remarkable history. It proceeds onwards 
a foot or so and takes a short rest, but produces a cluster of 
small tubers which make no leaves that season at least (Fig. 5), 
and then proceeds with another phase of growth terminating 
this time in a small plant, without the slightest trace of tubers 
(Fig. 6). The exact purpose of these tubers in the economy of 
the plant is not clear, and the solution yet awaits some careful 
observer. It is evident that the plant could exist and perpetuate 
its race without them, and probably quite as well, but as nature 
rarely makes anything that is of no use to the individual, and 
nothing that is wholly superfluous in the general good of the 
organic world, its exact relation is worth tracing. 
EXPLANATIONS OF THE PLATE.—1. Leaves and flowers from plants growing under Mr. 
Dawson’s care in the Arnold Arboretum. 2. The rayed stigma. 3. Upright root-stock of 
the past year. 4. New plant from the old one on a thready runner about a yard iong. 
5. Cluster of tubers. 6. Secondary plant of the same season, 
