PLATE VI. 



FIG. 91. 



FIG. 93. 



Dotted cells pith of Elder. 



Fio. 94. 



Circulation of fluid in hairs of Tradescantia 

 Virginica. 



Spiral cells : A, Balsam ; B, c, 

 Pleurothallis. 



FIG. 92. 



FIG. 95. 



Portion of the leaf of Sphagnum. 



Spiral fibres of seed-coat of Collomia. 



