120 



PLANT ANATOMY. 



A 



more or less needle-shaped; hexagonal 

 forms are also found, as well as mono- 

 symmetric and octagonal forms. In some 

 plants, Cortex Cinnamomnm, Bella- 

 donna. Dnicamara, the crj^stals exist as 

 crystalline "meaV that can only be 

 distinguished by means of the polari- 

 scope. Special forms have received the 



, /u 



C 



1— ... — p 



Fi;? 16.— Starch grains of Potato. (Sachs.) 



acting in this combination with iodine a 

 violet red or reddish brown. 



Mineral Salts. Salts of calcium, oxa- 

 late, carbonate, sulphate and phosphate. 



Calcium oxalate crystals are widely 

 distributed in plant cells, being found 

 in all parts of the plant save the cells 

 that functionally are used for purposes 

 of conveying plasma materials^ The 

 commonest form is that of crystals oc- 

 curring in clusters or singly. They are 



Fiff. 17.— Upper surface of leaf of Hyoscyamus, 

 showing oblong crystals, K. Also vessel bundles 

 f.v. (Vogl.) 



name of Rhapides, or needle-shaped; 

 Quadrangular, or rhomboidenal, and Ag- 



glomcratur, or clustered crystals. 



Calcium carbonate is less often found 

 than the oxalate. It may be in incrus- 

 tations covering cell walls or in the form 

 of cystollths, which are mulberry-like 

 masses; these are to be found in Canna- 

 bis, Hamulus and Ficus in abundance 



s 



^_p 



P 



Fig. 18. 



Kbizome Veratri. Longitudinal section of portion of root 



crystal sacs, Krs. EndodermU, Sp. Ducts. 



P. parenchyma, K, acicular 

 (Vogl.) 



