LEGUMINOS^ 643 



Colour and Brightness. — The coat of fresh good seed is 

 smooth and shining, of a brown colour. Old seed is darker 

 in tint ; imperfectly formed, unripe samples, which should be 

 avoided for sowing purposes, are yellow or greenish, with a 

 somewhat dull surface. 



Samples in which the seeds cling to each other are generally 

 damp and unsatisfactory, and often have a musty odour. 



Purity. — Commercial flax-seed often contains impurities, 

 the chief of which are lumps of earth and certain weed seeds, 

 especially Camelina dentala Pers., Polygonum lapathifolium L., 

 Black Bindweed {Polygonum Convolvulus L.), Bearbine or 

 Bindweed {Convolvulus arvensis L.), Knawels {Scleranthus 

 annuus L. and S. perennis L.), and Flax Dodder {Cuscuta 

 Epilinum Weihe). 



Germination Capacity. — For fresh seed this should be from 

 95 to 99 per cent. ; good stored older seed should not be lower 

 than about 90 per cent. 



Weight. — The absolute weight is very variable. In some 

 samples of Russian origin 1000 seeds weigh as much as 7-5 

 grams or more. Average good seed weighs 4*3 to 4*5 per 

 1000. 



LEGUMINOS.ffi. — This Order includes a number of valuable 

 plants, some of which are grown for their seeds, as beans and 

 peas, while others, such as vetches, the clovers, lucerne and 

 sainfoin are used mainly as forage crops, either cultivated sepa- 

 rately or in mixtures with grasses. 



The seeds vary very much in size, as we see when we compare 

 the Windsor bean with some of the clovers. 



The testa or seed-coat is generally leathery in texture, 

 tough and hard when dry, and nearly always bright and 

 smooth. While some of the seeds of this order are of uni- 

 form colour, as many beans and peas, they often exhibit two 

 or more colours, shading more or less into each other, as in 



