THE BONAVIST, LABLAB, OR HYACINTH BEAN. 3 



the flowers, and the size of the panicles. In many sorts the panicles are short 

 peduneled and 10 to 20 flowered, while in the more floriferous kinds the long- 

 stalked panicles are a foot in length and 20 to 30 flowered. 



Pods.— The pods vary greatly in size and shape (PI. I). The color may be 

 green, white, purple, or purple margined. In some of the green-podded sorts 

 the pods are fibrous and retain their shape when fully ripe, but most of the 

 cultivated varieties have more or less fleshy pods, which shrink and become 

 distorted at maturity. The fleshy-podded sorts are the best for use as snap 

 beans. 



Seeds. — The seeds vary greatly in size, shape, and color (PI. II), and fur- 

 nish along with the pods the easiest characters by which to identify varieties. 



Susceptibility to disease. — All of the varieties of the bonavist are remarkably 

 free from leaf diseases. Many, if not all, however, are subject to both Fusarium 

 root-rot and to nematodes. 



VALUE FOR HUMAN FOOD. 



The green pods of some varieties of the bonavist are much used 

 in the Tropics as snap beans ; indeed, they have been called by Rox- 

 burgh " the kidney beans of the Asiatics." Other varieties are not 

 thus eaten in India, being called bitter. One variety has for some 

 years been sold by Vilmorin under the name " Stringless " ( S. P. I. 

 No. 20447). This produces an abundance of large, fleshy white pods, 

 which, cooked after the manner of string beans, are very good. This 

 variety should be generally grown from Maryland and Kentucky 

 southward, as it not only produces an abundance of edible pods, but 

 incidentally makes an attractive arbor vine. 



The use of the dry seeds for food is less common, but some varieties 

 are thus utilized in India and China. 



Under some conditions prussic acid is formed in the seeds. Thus 

 Leather (8) 1 found that the poisonous acid was formed when the 

 crushed seeds of the bonavist were allowed to remain in cold water a 

 few hours. 



Mr. O. F. Black, chemical biologist of the Office of Drug-Plant, 

 Poisonous-Plant, Physiological, and Fermentation Investigations, 

 who upon request examined seeds of S. P. I. Nos. 8356 (blackish), 

 22025 (dark purple), and 25156 (cream color), all grown at Arling- 

 ton Farm in 1913, to see if hydrocyanic acid could be detected, made 

 the following report: 



The dry seeds were ground, suspended in dilute sulphuric acid, and distilled 

 witli >l<;iin. The distillate was tested for hydrocyanic acid, with negative 

 results in every <-ase. 



Nos. 83f»0 and 220li. r ) were germinated in the greenhouse in sphagnum moSS 

 until the roots were •''. to i centimeters long and then tested in a similar way, 

 hut gave no evidence of the presence of hydrocyanic arid. 



•'iii.- numbers lo parentheses refer i<> "Literature cited," page 15. 



