NEW CELL F0R1\L\TI0XS IN PLANTS 281 



In one or two cases isolated hard-bast strands were seen at the base 

 of the callus where it joined the wood, these probably having been left 

 behind after some little local disarrangement of the usual course of 

 events, such as irregularities in the form of the wound. The abnormal 

 areas might have been present close above or below the killed area and 

 have escaped detection. 



It is to be observed that the term "bark" is here used to denote 

 all outside of the bundle-cambium. The hard-bast elements in the 

 abnormal areas would come in time to be surrounded by wood, and, 

 by the formation of the new bundle-cambium come to be cut off from 

 the bark of the tree. The term "bark cambium" as used on pages 

 488 and 489 corresponds to the term "cork-cambium" used here. Dr. 

 Rumbold on this latter page also states that the presence of abnormal 

 lumps of cork visible on the surface of the trunk denoted the presence 

 of a disturbance of the cambium and phloem tissues beneath, by which, 

 in connection with her Figure 6 referred to, the writer understands the 

 production of abnormal xylem patches. In the specimen indicated 

 to the writer by her in the field as a case in point, and brought in for 

 examination no such relationship was seen. There was merely a little 

 superficial patch of cork. 



On page 489 she says "The inhibitory effect on the cambium was 

 transitory. In time a new cambium layer was formed, arising from 

 phloem cells." The effect on the original cambium was as permanent 

 as could be desired, since the cells became strongly lignified. It 

 was only the effect on cambial growth in general that was transitory, 

 tissue formation being taken up by the new cambium. 



The last point which the writer wishes to note is Dr. Rumbold's use 

 of the term "xylem." Thruout her paper it includes all lignified tissues 

 except the hard-bast and the stone-cells. The writer would strongly 

 favor limiting the meaning to those tissues that are composed of fibers, 

 pitted vessels, etc., and which only seem to arise from a secondary meris- 

 tem: that is, wood in the ordinary sense. This would exclude those 

 areas of phloem modified by Ugnification without special change of cell 

 form. 



Castanea — Summary 



The work on Castanea consisted of a microscopical examination 

 of the tissues of trees injected with various chemicals, and of the tissues 

 forming in the neighborhood of mechanical wounds, with a view to 

 the determination of the exact genesis and nature of the abnormalities 



