1868. ] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 459 



tance of these stolons with their tubers must be very considerable for 

 the propagation of the plant; but besides these tubers, with all their 

 buds, wecau find also in the axils of the leaves of the stolons small buds, 

 which are not only able to develop lateral branches, ending in tubers, 

 but also in some cases, as shown (Plate xlvi, Fig. 6), a short branch 

 with leaves of the same shape as those belonging to the stem. The de- 

 velopment of buds in this manner does not seem to be common, but I 

 have found it in some of the specimens collected along the Eastern 

 Branch. How far such a small branch may be developed I do not know, 

 but some of them showed, besides the leaves, also some very young 

 flowers, not perfectly developed, of which especially the calix and the 

 corolla were rudimentary or almost wanting, not unlike what are called 

 "clandestine flowers," but it is hardly probable that they are to be so 

 considered. There is, then, in the stolons a certain ability of taking on 

 the function of the runuers also, by developing leaves and flowers, 

 though these are not completely developed in the present case; but on 

 the other hand it must be remembered that they were found under 

 ground, therefore it seems that, had the conditions been better, they 

 might have attained a more perfect development. 



The other method of vegetative propagation in Hydrocotyle Ameri- 

 cana is by runners. These are developed from the axils of the leaves 

 of the upper part of the stem, as shown Plate xlvi, Fig. 2, and they 

 attain frequently a length of 1G centimeters. They are translucent and 

 have long internodes like the stolons, but are a little thicker than these, 

 and bear leaves of the same shape as those of the stem, only propor- 

 tionally shorter stalked. No buds were developed in the axils of these 

 leaves, or at least not in the state in which I had opportunity of exam- 

 ining them. 



Roots are developed under the leaves, but they seemed to be very 

 weak, and this circumstance, in connection with the somewhat feeble 

 development of the runners, does not make it probable that very ex- 

 tensive propagation takes place in that manner. The function of the 

 runners is to form new plants when they are provided with roots at 

 their nodes, and thereby creeping on the earth. But I have not been 

 able to find a single young plant originating in this manner, and it does 

 not seem probable that the runners could resist the frost of winter. 

 Possibly their character as runners depends on the circumstance that 

 they have not been able to bend themselves downwards before their 

 long internodes were developed, and that they might not have been 

 strong enough for penetrating the ground with their ends; for, as we 

 have seen, they are only to be observed in the axils of the upper leaves 

 of the stem. This last circumstance seems certainly to speak in favor 

 of the supposition, owing to their character as merely runners : for the 

 stem of our plant is a little ascending, so that only the branches from 

 the lower-situated leaves can reach the ground pretty soon, while it 

 ai ust be necessary for those from the axils of the upper leaves, the 



