438 LEGUMINOS^ 



Many sandy districts on the Continent which were practically 

 valueless have been very materially improved in fertility by the 

 utilisation of these plants as ' green manure.' 



Lupins contain a greater amount of digestible albuminoids 

 than any other known crop, and besides their use as a manure 

 are also used in a green state folded off by sheep; they are 

 occasionally made into hay. The plants contain a variable 

 proportion of a bitter alkaloid which makes them unpalatable to 

 horses and cattle, and sheep at first appear to dislike the crop. 



In addition to the bitter alkaloid, lupins under certain 

 indefinite conditions of soil, manuring, and storage sometimes 

 contain a poisonous compound named lupinotoxine, which 

 rapidly produces fatal results in sheep when the latter are fed 

 with even moderate amounts of the cut green fodder or hay. 

 Of the various methods to render the lupin crop perfectly 

 innocuous, heating with steam under pressure of one or two 

 atmospheres has proved the most certain. 



Lupins succeed best on dry sands or light sandy loams. On 

 light calcareous ground they do not grow satisfactorily ; even on 

 sand resting on a chalky subsoil they often fail. Stagnant water 

 in the subsoil or an excess of humus in the soil is also detri- 

 mental to their development. 



In the early stages of growth the tap root develops extensively 

 while the parts above ground grow very slowly. 



25. Yellow Lupin (Lupinus luteus L.). — This species is the 

 one most generally grown as a farm crop. It is an annual, with 

 erect hairy stem from 2 to 3 feet high. The leaves are palmately 

 compound with from seven to nine lanceolate leaflets. 



The inflorescences are loose pyramidal heads consisting of 

 several (five to twelve) whorls of bright yellow papilionaceous 

 flowers. 



The ripe legumes contain three or four seeds and are from 

 1 J to 2 inches long; they appear swollen at the seeds, and the 

 valves are woolly on the outside. 



