66 THE PLANT WORLD. 



creeks, as has already been said, are slow-flowing, a rod or two wide, 

 and the tangled growth of brush and large herbaceous plants is so dense 

 and vigorous along the banks as to frequently meet in the narrowest 

 places. When the ponds were made, the level of the water was raised 

 five or six feet, or in times of high water even more. The whole 

 swamp above the dam was submerged to this depth, making of it a 

 shallow, extensive pond. Each of the ponds mentioned above is more 

 than a mile in length and varying from a few rods to half a mile in 

 width. It is perfectly evident that there was no natural expansion of 

 the stream in width in any part of the pond. 



The trees of the swamp and the great majority of the shrubs were 

 killed outright and now only the stumps show above the surface of the 

 water. The trunks lie embedded in the mud at the bottom of the pond. 

 The aquatic species that grew in the creek immediately improved 

 their opportunity to spread into all parts of the pond. The Swamp 

 Loosestrife {Decodon verticillatiis) and the Button-bush {Ceplialanthus 

 occidentalis) occupy the shallower parts of the pond to the exclusion 

 of almost everything else. They are particularly abundant in the 

 northern part of the Jennings pond where they completely cover the 

 ground that is usually covered with water but is occasionally dry. 

 Here they cover, all told, many acres. In the deeper portions the 

 Hornwort {Ceratophylluvi demersiwi) literally fills the water. So 

 thick is the mass of plants that they seriously interfere with a boat. 

 The Water-shield {Brasenia purpurea)., the Yellow Pond Lily [Nyni- 

 ph(Ea adveiza)^ the sweet-scented White Pond Lily {Cast alia odorata), 

 and the Pond-weed {Potamegeton natans) are very abundant in the 

 ponds wherever the water is deep enough to support them. Some 

 other species occur but none of them have "run wild" to the same 

 extent that the species enumerated have. 



Before the ground was submerged, there had accumulated upon 

 it considerable quantities of humus, or muck. When vegetation on 

 the swamp was kiHed by overflowing them, an inviting bed was made 

 for the aquatics of the creek. A skilled gardener could scarcely have 

 made a more perfect aquatic garden than here exists. The plants 

 found food in abundance — virgin soil to them at least — and as a result 

 the ponds afford an instance of aquatic plants spreading beyond their 

 original confines in a manner very analogous on a small scale, to weeds 

 when they invade cultivated fields. 



Cornell University. 



Mr. John Donnell Smith, the well known authority on the flora of 

 Central America, has a valuable paper in the December number of 

 the Botanical Gazette., in which he describes a number of interesting 

 new plants from Guatemala and other Central American republics. 



