1897.] NATURAL SCIENCES OF PHILADELPHIA. 161 



NOTES ON UNDERGROUND RUNNERS. 

 BY IDA A. KELLER. 



Reduction to types is one of the most characteristic features of 

 modern biological science. That very important branch of botany 

 and zoology which is known as morphology has this for its sole ob- 

 ject. In all the variety of form and function which the plant world 

 offers we recognize only a few organs, viz. : root, stem, leaf and 

 trichome as distinct from each other, every part of a plant being 

 simply regarded as one, or a modification of one, of these fundamen- 

 tal forms. 



It is the same mental habit by which we are influenced in the 

 formation of our ideas regarding the life history of plants. We are 

 accustomed to unify the cycle of their existence ; e. g., we say that, 

 in general, a plant arises from seed, that it produces roots, a stem, 

 leaves and, finally, fruit, when the sequence is repeated. Although 

 in reviewing our past experience we are forced to modify our views 

 upon this subject, we do not hesitate to pronounce the foregoing the 

 typical plan of vegetable existence. The more carefully, however, 

 we investigate the development of plants, the more divergences we 

 find in regard to this recognized fundamental method. Especially 

 among the lower forms of vegetation it may be observed that repro- 

 duction by fruit gives way with great frequency to bud formations. 

 Nor in the higher forms is the beginning of the vegetable organism 

 to be found in the ovule as often as we are apt to suppose. Such 

 bud formations find expression here in the production of bulbs, 

 tubers, adventitious buds, runners, etc. 



So far as the resulting plant is concerned, there is no difference 

 visible, whether it was produced from seed or bud, and it is not un- 

 til we unearth roots in great numbers that we begin to realize how 

 great is the importance of the method of reproduction by buds in 

 assisting to clothe the earth with vegetation. Every botanist will 

 readily recall many illustrations of this point. One season I spent 

 much time in studying the formation of runners on the bulb of 

 Erythronium Americanum, and the result was surprising. Again I 

 dug, up a great number of the scaly bulbs of Oxalis violacea, and 

 found hardly one without one or more runners issuing from its base. 



