LofKjevity of Cut Floivers. 247 



This blocking may be caused by external factors, or by factors 

 "vvithin the plant itself. The most common external cause is the 

 development of bacteria in the water surrounding the stem. This 

 is especially likely to happen if flowers are placed in dirty vessels, 

 or vessels in which the water has been left standing for some time. 

 The bacteria enter the vessels of the stem at the cut end, the sap 

 being an attraction, and after a time form a complete block, jire- 

 venting the ascent of water. This may happen to practically any 

 plant, and the most effectual remedy is to change the water fre- 

 quently, and by so doing the accumulation of bactei-ia is checked. 



Internal causes of blocking are a great deal more difficult tf) 

 discover and define. There may be an exudation of wound gum 

 into the vess;eLs, or the parenchyma cells surrounding the vessels 

 may develop outgrowths which push their way into the lumina, 

 and finally form a pareiichyiiiatous tisxue completely blocking the 

 vessels, and very effectively retarding the ascent of sap. This con- 

 dition is known as the formation of a tylosis. 



In order to prevent withering in these cases, it will l^e necessary 

 to keep the vessels clear, either by preventing the exudation or the 

 abnormal growth taking place, or by dissolving it as rapidly as it 

 is formed. This will have to be done by placing the stem in some 

 solution which will perform the required action without at the 

 same time having any harmful effect on the living tissues of the 

 plant.^ 



The work was commenced with any plants that happened to be 

 blooming at the time, and various well known household metliods 

 for preserving flowers were tested. Placing the stems in boiling 

 water, removing the bark for some distance up the stems, and char- 

 ring the stems, all proved Equally unsuccessful witli the flowers 

 used. The only one found to be of the slightest use was in the case 

 of dahlias, Avliich, if inclined to droop, would wIrmi i»lac<,'d in 

 boiling water, very often completely revive. 



Chrysanthemums and wattles are very inclined to show sudden 

 abnormal drooping, and in one or two cases this was proved to l>e 

 due to the present of masses of bacteria blocking the vessels, while 

 in others what seemed to be a gummy precipitate coubl Ix' seen 

 in the vessels by examining a section of tlie stem. Since the block- 

 ing and conseciuent withering take place very rapidly, it is most 

 probably caused by an internal secretion of a giimmy nature. If 

 this is the case it should b- a])le to be prevented by ])laring the 

 stems, either in a solution v.liiili will cause a procii>itat inn on the 



