45G NOTES OX IIYDROCOTYLE AMERICANA. 



ii moist, shaded place, and which, he informed me, he had collected 

 several years ago, observing at the time sonii peculiar organs, appa- 

 rently small tubers, which evidently belonged to the plant. He was 

 unable to find descriptions of these organs in the systematic works, and 

 as he was unable to undertake their examination himself he requested 

 me to investigate them. The plants, on being carefully dug up, showed 

 a number of tubers, hanging by whitish stolons from the axils of the 

 lower leaves. I examined them, and found that the organs were true 

 tubers, each consisting of several nodes, and that they must undoubt- 

 edly be of considerable importance for the propagation of the plant. 



In presenting the results of this examination, I shall first make some 

 remarks upon the diagnosis of our plant by the different authors who 

 have described it. The preseuce of the tubers has been mentioned 

 recently by Dr. George Vasey,* who observed them in 18 S3 and pub- 

 lished a short note upon them, in which, however, he only mentions 

 their presence. He says: "I was surprised to see a number of whitish 

 threads hanging from the axils of the lower leaves. I found that near 

 the extremity of these was a short oblong or cylindrical tuber, and these 

 tubers were undoubtedly for the propagation of the plants." Dr. Vasey 

 also sent the plants to Dr. Asa Gray, who replied that he had often ob- 

 served the "threads," but never the tubers. 



It seemed somewhat singular that this plaut, one of our more common 

 species, should never have been more carefully examined b3fore and the 

 preseuce of these tubers detected, and I determined to look at th2 de- 

 scriptions of it in the systematic works. Iu Gray's Manual of Botany, 

 1870, the plant is described as having the "stems filiform, branching, 

 spreading, and creeping," but the author says nothing iu regard to its 

 subterranean organs, either of the root or of tne presence of any rhi- 

 zome, and I found the same to be the case in soma other systematic 

 works of a more recent date. Oa turning to the older authors, curi- 

 ously enough it is found that the fact of oar plant being " tuberiferous" 

 was mentioned more than eighty years ago by a French author, and 

 in such a manner that it can not be doubted that he had examined the 

 plant and found at least one tuber. This author is A. Michaux, who in 

 his Flora Boreali Americana, published in the year 1803, has written in 

 his diagnosis of Hydrocotyle Americana, "Radice tuberosa," and, as will 

 be shown later, even if his expression "radice" may not be correct, he 

 was evidently a careful observer, and is probably the first author who 

 mentioned the circumstance. 



On further examining the literature, of which unfortunately only a 

 small part is accessible to me, I found that a few years after Michaux, 

 Fr. Purshf had described the plaut as being " Herba glabra, tuberosa." 

 It was supposed that the plant would be very exactly described by 



* Tuberiferous Hydrocotyle Americana L. (Bulletiu of the Torrey Botanical Club, 

 Vol. xin, No. 2, 1886.) 

 t Flora America septeutr., Vol. i, 1816, p. 190. 



