468 
EDWARD F. WOODCOCK 
The mature fruit is an achene, triangular in cross section and 
brownish black in color. The seed is large, filling the cavity of the ovary 
and conforming to its shape. The broad, thin cotyledons of the em- 
bryo are variously oriented from one angle of the seed to another, 
and present in cross section the appearance of a much distorted letter 
S. Figures 25 and 26 will give some conception of the complicated 
form of these cotyledons. The shortly petiolate cotyledons follow the 
interior of the testa for some distance outside the starchy endosperm, 
in close contact with the aleurone layer, which is uniformly one cell 
thick as in Rheum Rhaponticum. The cotyledons lie face to face 
with their midribs together and the width of the blade on one side of 
the midrib of each cotyledon is about twice that of the other side. 
As a result of this unsymmetrical form of the cotyledons, one of them 
extends beyond the other, the smaller half of each cotyledon being 
enclosed by the corresponding half of the other. In the mature fruit 
the radicle is rather large and tapers to an obtuse point, being com- 
pletely enclosed by the basal portion of the cotyledons. The starchy 
endosperm is exceedingly irregular as a result of the peculiarly un- 
symmetrical nature of the embryo. The cotyledons do not extend 
quite to the base of the embryo sac in the mature seed according to 
Stevens, a space containing the remains of the undeveloped basal 
portion of the embryo sac, being always present in the chalazal region 
of the seed. In the mature seed the embryo has a well-differentiated 
vascular system, and the cotyledons have become differentiated into 
epidermal, palisade, and spongy tissue as well as conductive tissue. 
The germination of Fagopyrum esculentum presents some very 
distinctive features although in some respects there is a marked 
similarity to the conditions found in Rumex crispus. 
During the first two days there is very little external change except 
a slight enlarging of the seed. Internal changes are however very 
likely occurring for very soon the apex of the fruit becomes split along 
its angles. The aleurone layer shows marked activity in the enlarging 
of the cells especially in the micropylar and basal regions. As this 
enlargement occurs, the cytoplasm of the cells becomes alveolar and 
fine granules appear quite uniformly distributed through it much as 
in Rumex crispus. It is quite probable that there is associated with 
this activity of the aleurone layer, as suggested for a similar condition 
in Rumex, a secretion of a ferment which dissolves the starch of the 
endosperm. The digestion of the starch proceeds much as in Rumex. 
