124 NYMPH.^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 

 thick 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 w^ithout 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 tracino-. 



Explanations of the Plate. — i. Leaves and flowers from plants growing under Mr. 

 Dawson's care in liie 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 long. 

 5. Cluster of tubers. 6. Secondary plant of the same season. 



