1911.] 



Herbage Studies. 



473 



One specially interesting result of the work done at this time may be 

 mentioned here. The form of Lotus corniculatus which some botanists 

 regard as a mere variety and others as a distinct species, Lotus major or Lotus 

 uliginosus, which grows, as a rule, in damp situations, was found to be free 

 not only from hydrogen cyanide but also from the correlated enzyme. This 

 variety is distinguished by its rank growth and coarse tubular stem. 



The conclusion we arrived at last year was, therefore, that Lotus 

 corniculatus occasionally contained a cyanophoric glucoside and corresponding 

 enzyme but we had no reason to connect the presence of the glucoside with 

 any particular conditions either of soil or of climate. 



This year the first specimen of Lotus we examined was sent to us from 

 Portrush, in North-East Ireland, by Dr. J. Yargas Eyre, who early in May 

 found a dwarf form of the plant growing there in profusion on the sand 

 dunes. This proved to be rich in hydrogen cyanide and also contained an 

 active enzyme. Dr. Eyre obtained other specimens in Ireland during May ; 

 all of these were cyanophoric. 



At Whitsuntide, however, one of us tested a considerable number of 

 specimens in Ayrshire, in the Barrhill district, always without finding any 

 trace of cyanide ; but on going out to the coast at Ballantrae again a 

 stunted form of Lotus corniculatus was found growing in profusion on the 

 beach just above high-water mark and this plant contained both cyanide and 

 enzyme but other specimens obtained on the same day from the hillside over- 

 looking the beach and only a short distance from it were free from cyanide. 



Having found cyanide only in the two stunted forms of the plant grown 

 on sea-sand at the coast, we were led to think that the occurrence of the 

 cyanophoric glucoside might possibly be favoured by " starvation conditions," 

 especially as the conditions during the previous year and in the Ayrshire 

 district early in the present season had been such as to favour luxuriant growth. 



During the present summer specimens have been procured from many 

 localities ; the result of testing these has been to show that whereas last year 

 cyanide was rarely present, this year it has rarely been absent. We have 

 never failed to detect it in plants from the neighbourhood of Beading, grown 

 under all sorts of conditions, excepting always the form definitely recognis- 

 able as Lotus corniculatus var. major (uliginosus) ; wherever we have obtained 

 this form, it has always proved to be free from cyanide and we have also 

 confirmed our observation made last year that this variety is free from the 

 enzyme which occurs in the cyanophoric form. 



Plants growing this year under a great variety of manurial conditions on 

 the experimental grass plots at Bothamsted have always contained cyanide ; 



