X-RAY MICKOSCOPY 



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PI. II — Fig. 8: Crystalline formation recently found in Virginia creeper stem, not identified, X65 

 Fig. 9: Crystalline short stilettos shaped in cells of a bark rich in radio-opaque salts, X260 

 Fig. 10: Groups of cells containing iodine in a filamentous red alga, X250 

 Fig. 11: Sea urchins crystals of Ca oxalate in Pelargonium stem, X2G0 



Fig. 12: Extra-epidermic crystals recently observed on Virginia creeper stem rich in radio- 

 opaque salts, X260 



Fig. 13: Raphids of Ca oxalate; these bundles of crystals are those of Hyacinthus bulb, X98 

 Fig. 14: Quadrangular crystals, possibly weddellite, in Virginia creeper tissue, X260 

 Fig. 15: Ribs of Rosa leaf with opaque crystals; parenchjon shows numerous chlorophyllian 

 spots quite transparent, X50 



640 



