Monotropaceae with Reference to Ericaceae 95 



that the pores point upward. This is to insure pollination. 

 Pollen grains occur in tetrads in all of the Pyrolaceae except 

 P. secunda. 



In C. umbellate, the filaments have two lobes toward the base. 

 These bear numerous unicellular hairs along the margin. The 

 anthers are violet in color and attached nearer the pore bearing 

 end, and have two short horns opening by apical pores. 



The stamens of C. maculata are similar to those of C. umbellata 

 except that there are present on the margins of the lobes of the 

 filament uniserrate hairs composed of 2-3 simple cells placed 

 end on end. The anthers are attached near the middle. 



In P. rotundifolia and P. elliptica, the filaments are not lobed 

 and the horns on the anthers are very slightly developed. 



In P. secunda, the anthers are oblong, opening by large pores. 

 No horns are present. The pollen grains are single. 



In P. minor, the anthers are not horned. 



In P. chlorantha, the horns on the anthers are well developed, 

 being about 0.5 mm. in length. 



In P. aphylla, the horns are well developed, being about 1 mm. 

 in length. 



In Moneses uniflora, the filaments are awl-shaped, the anthers 

 are prominently two-horned, the horns 0.5 mm. in length. 



In Allotropa virgata, the stamens are described as having 

 slender filaments, "anthers short, lobed, unappendaged, extrorse 

 in the bud, introrse in anthesis, the sacs opening to near the 

 middle by a chink." (72). This is the only member of the Mono- 

 tropaceae that possesses the faculty of changing the position 

 of the anthers in the opening bud, thus forming a connection 

 between the Pyrolaceae and the Monotropaceae. Pollen grains 

 are simple as in all the other members of the Monotropaceae. 



In Monotropa hypopitys, the filaments are long, with unicellu- 

 lar hairs. They are pressed closely up against the ovary ex- 

 tending up to the stigmatic disk, the five opposite the petals 

 being shorter than those opposite the sepals. The anthers 

 are short, kidney-shaped, with transverse dehiscence, opening 

 into two unequal valves. 



The stamens of M. uniflora are similar to those of M. hypopitys. 



In Sarcodes sanguinea, the filaments are long, slightly ex- 

 panded at the base, extending up slightly further than half the 

 length of the corolla, lying in the grooves of the ovary, and 



