VEGETABLE CYTOLOGY 
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Compound grains more or less rod¬ 
shaped. 
2 to i5ju in diameter. 
Hilum: central. 
Lamellae: 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 35 n in diameter. 
Hilum: central, circular or triangu¬ 
lar with radiating clefts frequently. 
Lamellae: indistinct. 
Polarization cross prominent. , 
Bean Starch (Phaseolus vulgaris ) 
Ovoid, ellipsoidal or reniform shaped- 
simple grains, occasionally ob¬ 
scurely 3- or 4-sided. 
25 to 60/x in length. Generally from 
3°~35m* 
Hilum: central, elongated with bran¬ 
ching clefts.# 
Lamellae: distinct, concentric. In 
some indistinct. 
Polarization crosses shaped thus, X 
Pea Starch (Pisum sativum) 
Oval-oblong, ellipticolar sub-reni- 
form. 
1 5 ~ 5 1M in length. Generally from 
20-40/z. 
Hilum: similar to that of bean 
starch but less cleft or simply 
elongated. 
Lamellae: distinct, concentric. 
Polarization crosses similar to bean 
starch. 
Canna Starch (Canna edulis and other 
species of Canna ) 
Broadly elliptical, flattened, with 
beak or obtuse angle at one end. 
50 to 135/z in length. 
Hilum: excentric near narrower end. 
Lamellae: concentric and excentric. 
Polarization cross very distinct; fine 
play of colors with selenite plate. 
Sago Starch (Metroxylon Sagu) 
Ovoid, muller shaped, or irregularly 
3 or 4 sided with rounded angles. 
Some more or less gelatinised. 
Simple or 2, 3 or 4-compound 
30-60^ long. 
Hilum: eccentric often altered by 
gelatinisation. 
Lamellae: Excentric and concentric. 
Polarization cross distinct. 
4. Dextrin.—Dextrin is a carbohydrate made from starch (chiefly 
from corn or potato starch) by the application of heat (yellow 
dextrin) or by treatment with both heat and acids (white dextrin). 
It forms a paste with water, the yellow variety tending to swell up 
and dissolve much more readily than the white. When examined 
microscopically in alcohol mounts, the grains, while conforming in 
general outline to those of the type of starch from which the dextrin 
was prepared, nevertheless show more conspicuous striations and 
clefts. Corn dextrin shows distinct striations, whereas striations 
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