ioo Henderson — Comparative Study of Pyrolaceae and 



The epidermal cells of the ovarian wall are slightly papillate. 

 The style is short and thick, the stigma disc-like pentagonal. 



In Allotropa the ovary is five-lobed. It too is five-celled 

 at the base, one-celled above. There are ten small slightly 

 down-directed nectaries at the base of the ovary. 



In Neivberrya the ovary is five-lobed, five-celled at the base, 

 one-celled above. There are ten downward directed spur-like 

 nectaries at the base of the ovary (Fig. 9). The ovary and style 

 are pubescent with simple unicellular hairs. The stigma is 

 depressed capitate. 



In Cheilotheca the ovary is "fusiform, one-celled, narrowed 

 into the short cylindric style; stigma globose conical; placentae 

 six, parietal, bifid, the long branches on all sides covered by 

 numerous ovules" (31). 



In the Ericaceae a five-lobed, completely five-celled ovary is 

 characteristic. In the Pyrolaceae and Monotropaceae there is 

 every transition from a five-celled ovary with central placenta, 

 as in the Ericaceae, to an incompletely five-celled ovary with 

 the placentae deep parietal and almost meeting, as in all the 

 Pyrolaceae, also Sarcodes and Monotropa; to an incompletely 

 five-celled ovary with the placentae not so deep parietal, so 

 that there is a good space between them, as in Schweinitzia; 

 to Pleuricospora where the ovary is four-celled for only a short 

 distance, then one-celled above with parietal placentae that 

 are close to the ovary wall. Drude (12) states that all the 

 Pleuricosporeae are one-celled. The writer finds the condition 

 in Neivberrya as in the Pyrolaceae; in Pleuricospora 4-1 -celled 

 as above ; no material of Cheilotheca could be obtained for exam- 

 ination. Hooker (31) describes it as being one-celled with six 

 parietal bifid placentae. 



In Ericaceae the ovary is often covered with hairs, peltate 

 glandular in Rhododendron lapponicum; glandular and setaceous 

 in Ledum palustre; glandular in Phyllodoce coerulea. In the 

 Pyrolaceae and Monotropaceae simple hairs are present in 

 Chimaphila umbellata, in Monotropa hypopitys; and small papillae 

 are present in Schweinitzia odorata and Pleuricospora fimbriolata. 



The ovules in all three families are always anatropous. Corre- 

 lated with the great numbers of ovules produced in the Pyrola- 

 ceae and Monotropaceae, is the rather remarkable number of 

 pollen tubes developed from germinating pollen grains on the 



