70 Henderson — Comparative Study of Pyrolaceae and 



papillate hairs appear on transverse section. Internal to the 

 epidermis are two to three layers of thick-walled, then two to 

 three layers of thin-walled, cells forming the cortex. The 

 outer 3-4 layers of the phloem are heavily lignified forming an 

 area equal in width to the succeeding area of thin-walled phloem. 

 There is only one year's wood developed, but this is rather 

 large in amount (Fig. 5, 1), the entire area being one and a half 

 times in width that of soft and hard bast together. Internal 

 to the wood is a rather large area of pith composed of thin- 

 walled rounded cells with small intercellular spaces. 



In C. maculata the epidermal papillae appear more numerous 

 and more strongly developed than in C. umbellata. There is 

 an outer thick-walled area of three layers and an inner thin- 

 walled area of 3-4 layers of cortex. There are four layers of 

 thick-walled hard bast which is slightly greater in width than 

 the soft bast. The wood is not as strongly developed as in 

 C. umbellata, the width being equal to that of the soft and 

 hard bast combined. The pith is similar to that of C. um- 

 bellata. 



In P. rotundifolia the epidermis is not papillate. There are 

 two layers of thick-walled, three of thin-walled, cortical cells. 

 The hard bast is five layers in thickness, being much greater 

 in width than that of the soft bast. The wood is developed 

 about as much as in C. maculata, being equal in amount to the 

 width of the hard and soft bast together. 



In P. elliptica the appearance of the section is very similar 

 to that of P. rotundifolia. 



In Moneses uniflora the epidermis is not papillate. All the 

 cortical layers (5-6) are thin-walled. There are four to five 

 layers of hard bast that dip in slightly between the patches of 

 soft bast so that the latter does not form a continuous ring 

 as in all the preceding. Each patch consists only of a few 

 small thin-walled cells. Internal to these is a ring of wood 

 that is very poorly developed in comparison with all those 

 preceding. In width it is only slightly greater than that of 

 the soft bast patches. 



In Monotropa hypopitys the axis becomes more fleshy and 

 wider in diameter than in any of the preceding. There are 

 papillate hairs present that are more numerous and much longer 

 than in Chimaphila. Internal to the epidermis are about twenty 



