110 PLANT ANATOMY. 
ately very wide, and extended in the direction of the axis of the 
frequently elliptical granules (Fig. 44). 
The nucleus, as a rule, is located eccentrically, although it is 
central in the large granules of the cereals (Fig. 47) and in the 
small, round granules of very many plants." Occasionally sev- 
eral nuclei are found in one granule. 
The layers disappear in consequence of the abstraction of water, 
when the granules are observed under liquids free from water, 
such as benzol, paraffin, volatile oils, fatty oils, glycerin, or when 
they are warmed. Glycerin loses this property to a degree pro- 
portionate to the amount of water it contains. On the other 
hand, the distinction of the layers is also obliterated through 
their intumescence (by the addition of water), even by water 
at 60 to 70° C. ora still higher temperature, but even in the 
ae 
0074 
Fie. 36.—Starch granules from the rhizome of ginger (Hager). 
Fic. 37.—Starch granules with a stay-shaped hilum, from Tuber Colchici. 
cold by means of saturated solutions of. many bodies which are 
very readily soluble in water, such as caustic potassa or soda, 
potassium iodide, calcium chloride, sodium nitrate or acetate, 
and chloral hydrate. These substances increase the capacity of 
absorption of water by the starch to an enormous degree, far 
beyond the distinction of the separate layers just explained, so 
that these swell up to a uniform mucilage. 
If starch granules are pressed under the cover-glass, fissures 
and clefts are formed, which, proceeding from the cleft of the 
nucleus or from the periphery, form cracks having a course 
mostly at right angles with the layers. 
According to the very thoroughly founded and developed 
_ 1 The eccentricity in the case of Cyperus esculentus amounts to i, 
in Canna lanuginosa to #5. 
