Monotropaceae with Reference to Ericaceae 49 



In 1907, Charlotte Ternetz (77), in a paper "Ueber die As- 

 similation des Atmospharisches Stickstoffes durch Pilze," used 

 as the basis for her experiments endotrophic fungi in the roots 

 of Andromeda polifolia, Oxycoccus palustris, Calluna vulgaris, 

 Erica carnea, E. tetralix, Vaccinium myrtillus, V. vitis-idaea, 

 V. uliginosum. She states that, although hyphae are present 

 in the seed coats, no trace of the fungus can be found in any 

 other living part of the plant, except the roots. Rayner (63) 

 in an article on "Obligate Symbiosis in Calluna vulgaris" traces 

 the fungus from the roots through the whole plant to the seed. 

 She proves that the symbiosis in Calluna is obligate, for, unless 

 the seedlings become infected, they die. She also states that 

 ovarial infection is present in Ledum palustre, Rhododendron 

 ponticum (garden var.), Rhododendron indicum {Azalea indica, 

 garden var.), Leiophyllum buxifolium, Kalmia angustifolia, Pieris 

 fioribunda, P. japonica, Gaultheria acutifolia, Arctostaphylos 

 uva-ursi, Arbutus unedo, Vaccinium vitis-idaea, Pentaptergyium 

 serpens, Calluna vulgaris, Erica carnea. Jean Dufrenoy (14) 

 in "The Endotrophic Mycorhiza of Ericaceae" has reported 

 the presence of a fungal mycelium throughout the entire plant 

 of Arbutus unedo. 



All these cited are, however, still green, and have abundant 

 leafy branches with well-formed clusters of typically ericaceous 

 flowers. It seems that the more simplified greens and the 

 yellow and white saprophytic forms have been separated from 

 the Ericaceae to form the Pyrolaceae and Monotropaceae, and 

 that these three families in the order named form a continuous 

 series from autophytic to completely saprophytic plants. 



An aim of this paper will be to ascertain how far saprophytism 

 has caused gradual and traceable degradation changes similar 

 to those of the Burmanniaceae, Orchidaceae, and Gentianaceae. 

 Practically all typical ericaceous plants are shrubs, rarely trees; 

 some like Cassiope are sub-shrubby; in the Pyrolaceae Chima- 

 phila and the larger species of Pyrola are sub-shrubby; but 

 Moneses uniflora would hardly be regarded as other than a 

 herb; in the Monotropaceae all of the genera are herbaceous. 

 Another aim will be to find characters which unite the most 

 degraded saprophytes with the autotrophic Ericaceae, thereby 

 proving that the separation of the Pyrolaceae and Monotro- 

 paceae from the Ericaceae is artificial. 



