632 



HYDROCYANIC ACID IN PLANTS, 11., 



result followed. The glucoside alone had disappeared, the enzyme 

 was still active. 



A similar result was also obtained with grass which had been 

 air-dried for over three months. 



Seasonal variations of C. incompletus: — 



The author desires to express his indebtedness, and thanks to the 

 following gentlemen, for supplies of this grass, at the various sea- 

 sons: — Chief Inspector Symons, of the Stock Department; Stock 

 Inspectors C. Brooks, of Scone, and W. G. Dowling, of Forbes; 

 Police Inspector Nolan, of Forbes; Mr. J. H. Maiden, F.L.S. 



Other Couch-grasses. — Cynodon dactylon Pers., the common 

 couch grass of lawns was tested from various parts of the State. 



Digitaria didactyla Willd., the Sydney blue couch, is found in 

 certain isolated patches only, such as Hunter's Hill, Vaucluse, and 

 Botanic Gardens. These two grasses have always given negative 

 results for hydrocyanic acid, but in a number of instances they 

 showed the presence of an active enzyme capable of hydrolysing 

 amygdalin. 



Danthonia semiannularis is generally considered one of the most 

 valuable and nutritious of the native grasses. It gives a faint 

 reaction for cyanogenetic compounds, but towards the end of sum- 

 mer it is parched and dry, and is then quite free, till the autumn 

 rains renew the growth. 



January ... + faint. August ... + faint. 



April ... - November ... + faint. 



Samples of this grass were collected by Mr. Breakwell from 

 Narrabri, Wagga, Moree, etc., at the various seasons, and all gave 

 similar results, when tested. 



Diplachne dubia, a Mexican grass, cultivated in the Botanic Gar- 

 dens. This is one of the strongest cyanogenetic grasses tested. It 



