336 THE AMERICAN MONTHLY [Nov., 



rugose, veiny, longitudinally ribbed, or hairy. On the 

 carpels of the acliene forms are special provisions pro- 

 moting dissemination and planting. This we should ex- 

 pect since the carpels always invest the seed and the 

 achene forms are probably the more specialized. This 

 feature is seen in the long hairs of Clematis and Ane- 

 mone. 



There are two distinct layers in the carpellary walls ; 

 first, the inner epidermal layer lining the cavity of the 

 ovary ; second, the remaining parenchyma outside. The 

 cells of the inner layer are always elongated, mostly 

 square in cross section, and generally thick walled. In 

 most genera they appear like wood cells. This is the 

 layer which has been especially strengthened for protec- 

 tion in the achenes, and is comparatively thin in all pod 

 genera. 



The outer layer is several cells thick and composed of 

 parenchyma, except in Ranunculus where it is thick 

 walled. In Actaea and Hydrastis it becomes fleshy. In 

 some of the achenes the cells of the outer layer are 

 slightly elongated and overlap like shingles on a roof, 

 the serration thus caused pointing toward the base of the 

 carpels. The hairs arising between the cells necessarily 

 point downward at first, but immediately make a turn on 

 reaching the surface and point toward the style. 



In most of the pod forms the inner cells and ribs of 

 the carpels run horizontally, except near the base where 

 they are longitudinal. In the majority of the achenes 

 they are entirely longitudinal. In the Anemone group 

 the number of ovules has been reduced to one, while the 

 cavity has elongated below and contracted above, leaving 

 the placenta at the top of the cavity and the cells and 

 veins longitudinal. In Ranunculus the ovules are reduced 

 to one, while the elongation of the cavity, if any, has 

 been upward. 



The manner in which material was prepared for the 



