96 



completion or restoration of a plant body after injury without 

 regard to the manner in which it occurs. Pfeffer (Phys. of Pits, 

 trans, by Ewart, 2: 167. 1903) states that " only those cases 

 ought to be designated as regeneration in higher plants in which 

 the new parts formed after injury or loss exactly resemble in 

 number and position the organs that have been removed." Mc- 

 Callum (Bot. Gaz. 40 : 98. 1905) recognizes three forms of re- 

 generation as follows : " (i) The part removed is entirely restored 

 by the growth of cells immediately below the cut surface ; (2) 

 there is no growth of embryonic tissue at the wounded surface, 

 but at a greater or less distance from it the organization of en- 

 tirely new primordia which develop organs which replace those 

 removed ; (3) the organ removed is restored by the development 

 of already existing dormant buds." Dr. Kupfer (Mem. Tor. 

 Bot. Club 12 : 196. 1907) says "The word regeneration ought 

 to be limited to those cases in which an organ is formed, de novo, 

 at a place or under conditions in which it would not normally be 

 formed." 



In the broadest sense of the term this form of reproduction in 

 Drosera may be termed regeneration, but since it may occur on 

 portions of the plant which are still attached to the main axis, 

 without the apparent stimulus of injury, it seems better to place 

 it in the category of plants that reproduce by budding than as 

 an example of regeneration. However it is an illustration of a 

 principle which much of the work on regeneration teaches, that 

 the different forms of reproduction in plants may be arranged in a 



scale of slight gradations. 



Winifred J. Robinson 

 New York Botanical Garden 



• JUGLANDACEAE FROM THE PLEISTOCENE OF 

 MARYLAND * 



By Edward W. Berry 



Some years ago a very complete account of the Pleistocene 

 flora of Maryland was given by Dr. Hollick f who enumerated 



* Illustrated with the aid of the Catherine McManes fund. 



t Hollick, Maryland Geol. Surv., Pliocene and Pleistocene, 217-237, pi. 67-75. 

 1906. 



