BY r. SMITH AND C. T. WHITE. 8^ 



adopted was the action of hydrocyanic acid vapour upon 

 Guignard's soda-picrate paper, after jDlasmolysis of the 

 living cells by chloroform, which brings about the reaction 

 of the glucoside Avith the enzyme Avith which, so far as our 

 e^xperience goes, it is invariably associated. 



The list folloAving comprises 68 indigenous plants, 

 in 22 natural Orders, which have definitely been shown 

 to be cyanophoric in Australia. Further species of wide 

 geographic range recorded as containing hj^drocyanic acid 

 elseAA'here, but of which specimens could not be obtained 

 by us, are also listed but markedt- In view of the finding 

 of Armstrong and Horton'', that Lotus corniculatus may 

 contain no hydrocyanic acid in certain geographical 

 situations, and Petrie's^ negative results in New South 

 Wales with species of Graminoae, elsewhere cyanophoric, 

 the possession bj' these of cj^anogenetic properties is probable 

 rather than certain. 



Where possible the examination of each plant was 

 more than once repeated at seasonal intervals. The 

 periodicit}^ very frequently noted in the occurrence of 

 hydrocyanic acid in plants renders it possible that certain 

 species examined at one season only and found to be 

 negative in reaction might at other times have been 

 cyanophoric. 



Of the plants listed 13 are found in the Gramineae, 

 10 among the native ferns, and 9 in the natural order 

 Proteaceae. Passifloraceae and Droseraceae are also 

 prominently cyanogenetic families. We believe the order 

 Chenopodiaceae has not been previously recorded as 

 containing any cyanophoric plant. 



Twenty-two plants are recorded for the first time as 

 yielding hydrocyanic acid. 



Where interest attaches to the plant as a reputed 

 poison, or where from its herbaceous character, it is likely 

 to be eaten bj- stock, it is the subject of a special note. 



Magnoliaceae. 

 Drimys dipetala F.v.M. (Petrie, 1912). 



LiNACEAE. 



Linum marginale A. Cunn. (Petrie, 1912). 



