82 COMMERCIAL FEEDING STUFFS. 



The surface of the seeds is covered with mucilage cells which swell 

 in water or aqueous solutions, and take on a characteristic hour-glass 

 form. (Plate VI, fig. 1.) The endosperm cells are thick walled 

 and have no pits in them. (Plate VI, fig. 2.) The position of the 

 cotyledons is of the right-and-left type. (Plate V, fig. 4.) 



RIB GRASS. 



Plantago lanceolate L. 



These seeds are of about the same size as those of P. aristataMichx., 

 but have a bright brown to black color and no transverse depression. 



The surface of the seeds of this species is smooth, and has very 

 little of the mucilage layer found in P. major L. and P. rugelii Decaisne. 

 After being mounted in water or chloral hydrate the endosperm cells 

 swell and show prominent pits in their walls. The cotyledons have 

 the right-and-left position in the seed. (Plate V, fig. 3.) 



COMMON .PLANTAIN. 



Plantago major L. 



Seeds vary from 1 to 1.5 mm in length, and are about two-thirds i 

 as wide ; they are brown to black in color. These seeds are convex j 

 on both sides, not having the canoe shape which is characteristic 

 of the other species studied. (Plate V, fig. 1.) The surface is cov- 

 ered with an outer very uneven layer of thin-walled cells. They are 

 rather long, rectangular in form, and with quite uniformly wavy 

 walls. (Plate VI, fig. 3.) They are arranged in rows with the long 

 sides of the cells adjacent and at the ends where adjacent rows abut j 

 there is usually produced a ridge which, until well cleared, appears 

 as a dark band. The endosperm cells show no beading in their walls. 

 The cotyledons have a dorsal and ventral position in the seed. 



RUGEL'S PLANTAIN. 



Plantago rugelii Decaisne. 



These seeds vary in size from 1.25 to 2 mm and are of a deep- 

 brown or black color. 



In some respects they resemble more clearly P. major than any 

 of the others which we have studied. The cotyledons have the ven- 

 tral and dorsal position in the seed (Plate V, fig. 2). The epidermal 

 layer (Plate VI, fig. 4) consists of rectangular cells shorter than those 

 of P. major, and, though they commonly are arranged in rows, they 

 are rarely found to be continuous for more than eight or ten cells 

 together, and the rows are not regularly parallel as in P. major. 



