6 botanical gazette. [January, 



are these corky outgrowths, and is the advantage secured com- 

 mensurate with the outlay of the material ? It is not daimed, 

 however, that the results of the present investigations are such 

 as to render possible a satisfactory answer to these questions. 

 It is hoped that the few thoughts which have suggested 

 themselves in this connection maybe of some slight value. 



The earlier researches made on the subject of cork seem 

 to have fixed its use in the plant economy, as that of protec- 

 tion, mainly in the way of a substitute for epidermal tissue. 

 This certainly is the office of periderm, both superficial and 

 internal. Later investigations have somewhat broadened 

 the meaning of the word; cork tissue has been defined, 1 

 "Not simply the tissue produced bv cork cambium, but all 

 parenchymal cells which produce resin and which have a 



corkv memhranp in rrt.not-.il A <ir»,-«. ^~n ...u:..u \ _ ___i 



Accep 



corky 

 ude as 



- . . i rt —■w~.«« MV m, vv^ muai inhume cl.-> 



part ot its function the repairing of tissues torn or broken 

 by external or internal causes and aiding in the regulation 

 of gases and transpiration. 



We have already referred to Hohnel's division into phel- 

 loid and real cork-cells ; to the former he gives two func- 

 tions— first, to separate the bark from the stem, "Trennungs- 



P k i-H s ? cond ' totak e the place of the real cork, "Ersatz- 

 phelloid. According to the strict definition of bark, the 

 first function can not be ascribed to the phelloid of the wing, 

 nor, in fact, to that of any found in the superficial periderm. 

 lhe second function means nothing unless we are able to de- 

 cide what use the real cork would be to the stem if occurring 

 in the same place. h 



BM fi e 2l^f5 th t! a . ri0,18 . , ? nds 0fwin S 8 were subjected to the 

 cies ,nd 1 , SUbenn ' WUh Var >' in S results in the same spe- 



Slr ei T S eV6n m sections cut from different places 

 in tne same plant. r 



mac^ratW fl° f ^ u } di \ mhar thoroughly heated in SchulzeY 

 showed hf f n - nd thei ! treated with chlor-iodide of zinc, 



ler 11 r ng , reSUltS : In n ° Si % rle ™ s e did all the 

 of Z of h ° W ^ PUre . ]i ^ neOUS re ^tion. The walls 

 mree or fLt ^ Contained ™re or less suberin. In 

 mens were tr^'T^ '" whidl a Iar S e numb *r of speci- 

 lTgneou f F?n* ■ ii the gre u- ter 1 mimber of these cells were 

 mw cells o Tr\ f Y Wa U hlS the Case with the early sum- 

 STSSw^T!?' T-i ,S 1 indiCates that these "lis are 

 the nhelloin In '^ mi1 ^ reach some dist ance from 



!r_l!lf!!??f!L^ alwavs showed the 



'Byh.Adlerz. See abstract in j U8 f s Jahmsbericht. XI U 8tf>. 52.V " 



