92 Henderson — Comparative Study of Pyrolaceae and 



In Cheilotheca there are 3-4 oblong lanceolate sepals (31). 



In the Ericaceae, the sepals are usually green or brownish 

 (exceptions to this occur as in Cassiope hypnoides with a red 

 calyx), generally united, at least at the base. In Kalmiella 

 and Cladothamnus pyrolaeflorus, the sepals are almost distinct. 

 In a few the sepals are distinct as in Epigaea repens. All of 

 the Pyrolaceae are similar in this characteristic to the Eric- 

 aceae — the sepals all being slightly united. In the Monotro- 

 paceae, Pterospora has a slightly united reddish brown calyx 

 with narrow linear to lanceolate lobes. Sarcodes has a slightly 

 united calyx, but the sepals are petalloid, crimson and large, 

 almost as long as the corolla. In all of the other genera, the 

 sepals are separate, 5-4-3 in number and petalloid, showing a 

 gradual transition from small green united sepals in Ericaceae 

 to large petalloid distinct ones in the most reduced members of 

 the Monotropaceae. 



In the Ericaceae, the sepals are often hairy, the hairs similar 

 to those found in the Pyrolaceae and Monotropaceae. In 

 Cladothamnus campanulatus, for instance, simple hairs like 

 those of Monotropa hypopitys and stalked glandular hairs like 

 those of Pterospora and Sarcodes occur. 



The Petals 



In C. umbellata, the petals are five, separate, concave, orbicu- 

 lar, pinkish in color, and 5-6 mm. in length. Under the micro- 

 scope they show a fimbriolate margin that is ciliolate with 

 numerous unicellular hairs. 



In C. maculata, the petals are similar to those of C. umbellata 

 except for the color, which is white. 



In P. rotundifolia, there are five distinct, spreading, white, 

 concave, roundish-obovate petals, about 7 mm. long with an 

 entire margin. 



Those of P. elliptica are similar except that they are greenish 

 white in color and are about 6 mm. long. 



In P. secunda, there are five oblong or elliptic erect petals, 

 4-5 mm. in length, greenish white in color. 



In P. minor, there are five white or rose-colored, orbicular, 

 concave, erect petals, 3-4 mm. in length. 



In P. chlorantha, there are five greenish white, oval or elliptic, 

 petals, 5-6 mm. in length. 



