LISTS OF PlIKPAUATIOXS 219 



lengthwise sections of ovules after fertilization, sliowin^ embryo in embryo 

 sac, safranin and D.'s luomatoxylin. 



213. Slides of value in histological studies on the seed plants. 



ROOTS 



Corn root tip. Lengthwise section, showing plerome, periblem, and dor- 

 matogen, safranin and Delafield's haematoxylin. 



Tradescantia root tip. Lengthwise section, showing general root struc- 

 ture and nuclear division, safranin and gentian violet. 



Smilax root. Cross section, showing cortex, endodermis, and radial 

 bundles, safranin and D.'s haematoxylin. 



STEMS 



Hippuris shoot. Lengthwise section of stem apex, showing meristem, 

 origin of lateral shoots and leaves, safranin and D.'s hiematoxylin. 



Indian corn stem. Lengthwise section, showing sieve tubes, companion 

 cells, annular tracheids and sclerenchyma, safranin and D.'s hieniatoxylin. 



Pumpkin stem. Lengthwise section,. showing sieve tubes and companion 

 cells and vessels, safranin and D.'s hematoxylin. 



Menispermum stem. Cross section, showing separate bundles of a climbing 

 stem with large vessels for conducting water, safranin and D.'s luematoxyHn. 



Brasenia stem. Cross section, showing typical structure of an aquatic 

 stem with large air cavities and scanty vascular system, D.'s h;ematoxylin. 



Dodder on golden-rod stem. Cross section, showing penetration of stem 

 tissues by haustoria, safranin and D. 's haematoxylin. 



LEAVES 



Cycas revoluta. Cross section, extremely xerophytic leaf structure witli 

 thick cuticle, highly developed palisades, and depressed stomata, safranin 

 and D.'s haematoxylin. 



Peperomia. Cross section, typical of water storage in the leaf outside of 

 the photosynthetic tissue, D.'s hiematoxylin. 



Silphium laciniatum. Cross section, vertical k^af with a palisade layer 

 near each surface, D.'s hematoxylin. 



Potamogetni. Cross section, submerged leaf with thin epidermis, no sto- 

 mata nor palisades, large air cavities and scanty vascular system, D.'s 

 haematoxylin. 



Water buttercup. Cross sections (1) of aerial leaf ; (2) submerged leaf, 

 D.'s hgematoxylin. 



