BUCKWHEAT 583 



of plant give rise to both kinds, and the ratio is not 

 influenced by fertility of the soil. Cross-pollination 

 between plants is supposed to be facilitated by this 

 provision. 



Blossoming begins when the plant is still immature and 

 continues uninterruptedly until the plant is killed by frost 

 or is harvested. There may be then on the same plant 

 both flowers and mature kernels. After the plants are 

 cut many kernels may mature 

 while in the swath or shock. 



645. The buckwheat kernel is 

 in the form of an achene, it being 

 a single seed inclosed in an in- 

 dehiscent pericarp that fits tightly 

 around the seed. The achene is 



, . FIG. 174. Form of kernel 



3-angled, the angles being acute, in 3 different varieties of 

 and has the form of a pyramid buckwheat: a, Tatarian; 



. , , , , , ,-r,. ., ._ . b, Japanese ; c, Silver 



with the base rounded (Fig. 174). Hull. 

 The hull or pericarp varies from 



silver gray to brown or black in color and is hard and 

 thick, with the surface polished and shining. It separates 

 readily from the mealy endosperm. The grain varies 

 usually from A to f inch in length and from i to A 

 inch in width. The relatively large embryo is central, 

 dividing the soft, white endosperm into two parts, the 

 cotyledons being broad. The surrounding testa is mem- 

 branous and light yellowish-green in color. 



646. Classification. Buckwheat belongs to the Poly- 

 gonacese, or buckwheat family. Several of the common 

 weeds, such as dock, smartweed, bindweed, and sorrel, 

 knotweed, and the like, belong to this family, but not to 

 the genus Fagopyrum, the name which has been given to 

 the buckwheats. In this genus there are several species, 



