96 Henderson — Comparative Study of Pyrolaceae and 



bearing on their apices the rather long expanded anthers which 

 open by two oval pores at the summit, turned toward the outside. 



In Pterospora, the filaments are slender, the anthers short, 

 each sac with an awn. The dehiscence is longitudinal. 



In Pleuricospora, there are 10-8 stamens; the filaments are 

 long and glabrous, the anthers long and narrow, opening by a 

 longitudinal slit. 



In Schweinitzia odorata, the anthers are short, opening by 

 terminal pores. 



In Newberry a, the stamens are 10-8 in number; the filaments 

 are slender with long hairs. The anthers are oblong, erect on 

 the tip of the filament, opening lengthwise. 



In Cheilotheca, the anthers are erect on the filaments, and 

 have longitudinal dehiscence (31). 



In the Ericaceae, types of stamen similar to all those of the 

 Pyrolaceae and Monotropaceae are present. Many of them 

 have hairy filaments, as in Chimaphila and Monotropa. Simple 

 oblong anthers occur as in P. minor, P. secunda, and Sar codes 

 with apical pores and not horned, e. g., Kalmia glauca (12, p. 26, 

 Fig. 17); others with exceedingly long tubes, as in Vaccinium 

 vitis-idaea (12 Fig. 17) longer than in any of the Pyrolaceae 

 and Monotropaceae. In the Pyrolaceae and Monotropaceae 

 dehiscence of the anthers occurs in the same way as in the 

 Ericaceae. Apical porous is quite common. Longitudinal de- 

 hiscence also occurs in practically all groups of the Ericaceae. 

 In the Rhododendroideae-Ledeae, Elliottia and Cladothamnus 

 have longitudinal, Bejaria and Ledum apical porous dehiscence. 

 Transverse dehiscence occurs in the group Arbutoideae-Andro- 

 medae. 



In the Ericaceae, the anthers may or may not be awned. 

 In Figs. 17 and 18, p. 26, Drude (12) has figured Erica tetralix, 

 Arbutus unedo, Calluna vulgaris with awned anthers, Vaccinium 

 vitis-idaea, Kalmia glauca, Rhododendron flavum , and Leiophyllum 

 buxifolium without awns. As a general rule the more primitive 

 members of the Ericaceae with open flat expanded flowers do 

 not have awned anthers, those with urceolate corollas gener- 

 ally do. This rule also applies to the Pyrolaceae and Mono- 

 tropaceae; Pterospora the only member with awned anthers, has 

 an urceolate corolla. The awns when touched by an insect 

 tilt the anthers so that the pollen is dropped out on the insect's 

 back. 



