90 Henderson — Comparative Study of Pyrolaceae and 



Monotropa hypopitys, Sarcodes, Pterospora, Pleuricospora, 

 Schweinitzia, Allotropa have racemose inflorescence; Chimaphila, 

 and Newberrya corymbose; Moneses uniflora and Monotropa 

 uniflora solitary terminal flowers, thus forming a series parallel 

 to that of the typical Ericaceae. 



The bracts in the Ericaceae are generally small, green, often 

 deciduous as in Chimaphila and Pyrola. In the Monotropaceae, 

 they have become much larger, and like the fleshy scale-like 

 leaves. There is a transition from forms like C. umbellata and 

 C. maculata, with no scales on the flowerstalk, to P. rotundifolia, 

 P. elliptica, P. minor, P. chlorantha, Moneses uniflora with 1-2 

 scales; P. secunda with generally 4; P. aphylla with still more 

 numerous scales and no, or rarely, green leaves, and finally 

 to Monotropa, Sarcodes, Pterospora, Pleuricospora, Schweinitzia, 

 Allotropa, and Newberrya, where the scales are very numerous, 

 fleshy, entirely replacing green leaves at the base and becoming 

 only slightly modified toward the flowers. 



In the Ericaceae the plants live for two or more years before 

 flowering and the flower buds appear in the autumn of the year 

 preceding their expansion. This also occurs in all members of 

 the Pyrolaceae. In the Monotropaceae the underground part 

 lives for a year before sending up a flowering axis and buds do 

 not appear above ground until the spring, when they are ready 

 to expand — this of course due to the fact that the ascending 

 axis in the Monotropaceae is annual. 



The Sepals 



In Chimaphila umbellata there are five green sepals united 

 at the base. The lobes are rounded, about 2 mm. in length, 

 and appear entire. Under the microscope, however, the margin 

 appears slightly fimbriolate. 



In C. maculata, there are five small oval sepals, united at the 

 base. The segments are slightly longer than in C. umbellata, 

 being 3 mm. in length, about one-fourth the length of the petals. 

 Simple unicellular hairs are present along the margin. 



In P. rotundifolia there are five green sepals united at the 

 base. The five lobes are lanceolate acute with spreading tips 

 and are 3-3.5 mm. long, one-half to one-third the length of the 

 petals. 



