NON-PROTOPLASMIC CELL CONTENTS 81 
BARLEY STARCH (Hordeum distichon) 
Grains having a similar shape to those 
of wheat starch but frequently tending 
to bulge on one side and so appear 
sub-reniform; large grains smaller; 
simple. 
Grains appear elliptical to lemon 
shaped in edge view. Large grains 
usually 18 to 25u, occasionally up 
to 30y in length. 
Hilum: centric or circular or cleft, 
often indistinct. 
Lamellz: concentric in partly germi- 
nated barley; usually indistinct. 
Polarization cross distinct. 
BucKWHEAT STARCH (Fagopyrum 
esculentum) 
Grains simple and compound. 
Simple grains polygonal or rounded- 
polygonal. 
Fic. 45.—Potato starch, polarized as 
d starch under polarized light. 
BucKWHEAT STARCH 
Compound grains more or less rod- 
shaped. 
2 to 15u in diameter: 
Hilum: central. 
Lamellz: generally indistinct. 
Polarization cross distinct. 
CassAvA STARCH (Manihot 
utilissima) 
Grains rounded, truncated on one 
side. 
Simple or two- to three- or four- to 
eight-compound. 
6 to 35u in diameter. 
Hilum: central, circular or triangular 
with radiating clefts frequently. 
Lamellz: indistinct. 
Polarization cross prominent. 
Arrowroot 
Note that 
Fic. 46.—Maranta or 
viewed by light passing through crosse 
nicol prisms of a petrographic microscope. 
(Schneider.) 
the two dark bands cross at the hilum of 
each starch grain. (Schneider.) 
