80 COMMERCIAL FEEDING STUFFS. 



BINDWEED, SMARTWEED. 



Polygonum sp. 



The seeds of P. convolvulus L. have the form of ^buckwheat grains, 

 being about 3 to 3.5 mm long, and of a dull, coal-black color. P. 

 pennsylvanicum L. has flat seeds 3 to 3.5 mm long, of shiny brown 

 color. The seeds of P. persicaria L. are about 1 to 1.25 mm long, 

 generally flat, though occasionally buckwheat-shaped specimens are 

 found, and of a shiny deep brown or black color. P. hydropiper L. 

 seeds are of buckwheat shape, like P. convolvulus, but of smaller size 

 (2.5 to 3 mm) and of dull light to dark brown color. 



The seed coats of the members of the genus Polygonum persicaria 

 are commonly so deep brown in color that considerable boiling is 

 frequently required to clear them sufficiently for examination. When 

 satisfactory clearing has been accomplished the surface of P. persi- 

 caria is found to have a dotted appearance, the dots being arranged 

 somewhat in rows. If the specimen is sufficiently cleared the pits 

 can usually be seen as fine lines radiating' through the clearer portion 

 of the walls between the dots or holes, which in reality are holes in 

 the epidermal cells. (Plate VI, fig. 5.) 



WILD BERGAMOT. 



Monarda fistulosa L. 



f 



These seeds are pale to dark drab in color, 1.5 to 1.75 mm in length 

 by about 1 mm wide ; one side is curved, while the other is compressed 

 into a ridge near the base, which is more or Tess common in the mint 

 family. 



The seed coats are characteristic. The epidermal cells have thick 

 walls of very strongly convoluted outline. (Plate II, fig. 4.) The inner 

 part of the coat is lined with a layer of thin-walled rectangular cells, 

 the walls of which have a beading which is more pronounced near the 

 hilum of the seed. The perisperm is a layer of delicate cells covering 

 the endosperm and having quite strongly beaded walls. Embedded 

 near the middle of the seed coats, at fairly regular intervals, are small 

 black dots of spherical form, which appear plainly in either the surface 

 or inner view of well-cleared fragments of the seed coats and also in 

 cross sections. By continued boiling with chloral hydrate they may 

 be bleached so as to be almost invisible. Examination of other 

 plants of the mint family indicates that these dots occur in other 

 genera also, for example, in Hedeoma pulegioides Pers. 



cow IIKHB. 



Vni-i-iiriii nii-i-iiriii (\..\ Brit ton. 



The seeds of this weed are blue black i^ color, nearly spherical in 

 shape, and about 2 mm in diameter. To the naked eye the surface 

 has a slightly dull appearance. Microscopically the seed coats are 



