266 



Botanical Notes, 



riate XCIV. 



In the September number of the Botanical Gazette for i88i 



Nastiir- 

 ttim lactLstre. Having had doubts as to the correct interprcfation 

 of the facts, this plant has since been re-examined and the accom- 

 panying figures prepared. The plant is aquatic ; its lower leaves 

 are pinnately dissected and immersed, the upper leaves are more 

 simple, usually ovate-oblong, and emersed, although towards 

 the close of the flowering season all leaves are apt to be more or 

 less under water. About the middle of August the pinnate 

 leaves break off and float on the surface of the water. At their 

 base, in the place corresponding to the axil, a few very small 

 leaves appear in a cluster, from which a few days later a branch 

 begins to develop, in a direction opposite to the parent leaf, at 

 the end of which a cluster of leaves forms a rosette, which floats 

 on the surface of the water. From the very first a number of 

 roots appear, which grow along the upper surface of the floatin 

 parent leaf in a direction towards its apex. This growth of the 

 roots up the inclined base of the petiole where it must be exposed 

 to the light was different from what has been observed elsewhere 

 in the growth of roots, and this led to a re examination of the 

 plant. It would seem a much more natural course of events if 

 the roots would immediately bend over the ed<^es of the petiole 





and seek as well as they could the darker side beneath. No such 

 effort, however, seems to be made until the roots are from one- 

 fourth to one-third of an inch in length. Soon after the new 

 branch has grown so long and the base becomes so much thick- 

 ened that the end to which the old leaf is attached gradually sags 

 downward into the water, and in due time the roots have grown 

 long enough to touch the bottom and fasten the plant. The old 

 leaf simply decays. It is now quite certain that the roots do not 

 derive food from the parent leaves, but why they should seek the 

 upper surface seems very strancre. 



It has been customary to notice from time to time the autumn 

 flowering of our spring plants. Perhaps, considering the regular- 

 ity with which the warmer seasons of autumn, called Indian sum- 

 mer, come to our northern States from year to year. It were just 



