12 THE DESCRIPTION OF WHEAT VARIETIES. 



The ligule (PI. Ill, fig. 1) is the thin, transparent tissue borne at the 

 juncture of the blade and sheath of the leaf and clasping the stem 

 above the leaf. The terms long, medium,, and short apply to the height 

 this tissue reaches up the stem. A ligule 2.5 mm. or longer is con- 

 sidered long, while one 2 mm., more or less, is medium, and it is short 

 when less than about 1.7 mm. 



The leaf auricles (PI. Ill, fig. 1, No. 2) are the thin projections of 

 tissue which are the outgrowths from the base of the leaf blade or 

 from the thickened tissue at the juncture of the blade and sheath of 

 the leaf. The terms applying to these need no explanation. 



Mature plant. — The height measurement is. marked to be stated in 

 centimeters and, whenever possible, should be made when the plant is 

 still standing in the field in its natural position. The terms strong, 

 medium, and weak apply to the general vigor of the plant, including 

 its ability to stand erect and its branching or "stooling." The diame- 

 ter Mow the head should be measured at the point where the straw is 

 smallest, between the upper leaf and the base of the spike. "When 

 this measurement is made some sort of calipers must be used. The 

 terms furrowed, nn dium, and smooth apply to the surface of the straw, 

 and these terms should be used only where straws may be compared 

 side by side, as all wheat straws are more or less furrowed. 



The terms solid, semisolid, and hollow (PI. V, figs. 1, 2, and 3) apply 

 to the amount of pith in the culm about halfway between the top of 

 the upper leaf sheath and the base of the head, solid being used when 

 the straw is entirely full of the pith, semisolid when only a very small 

 hole through the center of the straw is open, and hollow when the 

 pith is entirely absent or consists only of a thin layer on the inside of 

 the culm. 



The terms thick, medium, and thin applied to the Avails of the culm 

 are relative, and can be stated only after comparing different plants. 

 In considering the thickness of the walls, the layer of pithy tissue on 

 the inside must not be included as part of the wall. The thickness of 

 ' the wall indicates to some extent the rigidity of the culm and the 

 ability of the plant to stand erect. 



The color terms here are applied to the culm after the plant is com- 

 pletely matured and are, as before, only comparative. 



The terms scanty, medium, and abundant, applying to the foliage, 

 should be marked only when opportunity is had of seeing various 

 plats of grain together under similar conditions. 



The percentage of rust for leaves and stems must be estimated, con- 

 sidering 100 per cent damage in either case as applying to cases where 

 the surface of the leaves or stem is completely covered with rust 

 pustules, and zero per cent when no rust is observed. This estimate 

 may be based on a single plant or on a whole plat of grain, as occasion 

 requires. 



When estimating smut of either sort the same is true. When every 



