FLOWER STRUCTURE 



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Plate 64. — Flower Structure. 



Powdered Arnica Flowers. 1. Pollen grain. 2. Glandular trichome (unicellu- 

 lar). 3. Glandular trichome (multicellular). 4. Nonglandular trichome (unicellu- 

 lar). 5. Nonglandular trichome (multicellular). 6. Nonglandular trichome (mul- 

 tiseriate). 7. Stamen tissue. 8. Stigma tissue, showing papilla!. 9. Nonglandu- 

 lar trichome (bicellular). 10. Petal tissue. 11. Petal tissue, showing spiral vessel. 

 12. Calyx tissue. 



