134 



PART II. — VEGETABLE HISTOLOGY. 



In those parts of plants which are removed from the light, 

 and serve for the storage of reserve food materials, as seeds, 

 tubers, etc., analogous bodies called 

 amyloplasts are found. These are trans- 

 parent, or faintly yellowish corpuscles, 

 whose function appears to be to form 

 starch-grains. In some plants the starch- 

 grains are formed in their interior the 

 same as in chlorophyll bodies, in others, 

 on their surface. In Phajus grandifolius 

 an Orchid, they may be seen attached to one 

 end of the forming granule. See Fig. 375. 

 Aleuronc grains constitute another mod- 

 Wi VjAjf& n ification of protoplasm. This is one of 



)) the forms in which reserve proteid matter 



Fig. 374.— From upper side is stored up in the seed. They are more 

 Th^nn1r T TaU°of m ari P i: abundant and of larger size in oily than 

 STbolicV^Sj^S 1 " in starchy seeds. In shape they are usu- 

 abou^ralamete^S ally more or less rounded; most of them 

 strasburger. contain a small, roundish or amorphous 



mass of mineral matter, composed of the double phosphate of 

 calcium and magnesium, called a globoid ; occasionally they con- 

 tain crystals of calcium oxalate, and 

 not infrequently the larger ones con- 

 tain crystalloids, Fig. 376. 



Fig- 375- 



Fig. 376. 



Fig. 375. — Two starch grains from Phajus grandifolius, showing nucleus at the apper 

 end, and the amyloplast attached to the lower. Magnified about 1,000 diameters. After 

 Schimper. 



Fig. 376.— Cell from the Castor Bean (Ricinus communis), showing aleurone grains, 

 etc., a, aleurone grain, containing globoid and crystalloid; b, globoid; c, crystalloid. Mag- 

 nified about 1,000 diameters. After Sachs. 



Crystalloids constitute another of the resting forms of proto- 

 plasm. They have the shape and appearance of crystals of 

 mineral matter, but differ from them in the fact that they swell 



