Lecture XII — 175 ^ Mycotrophic Phagocytosis 



LARius, 1928). In Pogonia the fungus seems never to penetrate 

 deeper than the inner cortical cells (Carlson, 1938). In Neottia the 

 3-4 outer layers of cortex are infested (Magnus, 1900) while the 

 fungus never penetrates the central cylinder which, said Magnus, 

 ''seems a remarkable localization". Pittman (1929) found that the 

 fungus never penetrated Rliisantliclla tubers. Ames, who saw (1922) 

 that the vascular tract of Goodyera is never invaded, remarked (1921) 

 that certain areas of the orchid root {sic) seem able to repel advance 

 of the fungus; and "it is as if there were some fungicidal capacity 

 in the cells of the root structure that restricts the fungus to a limited 

 area." 



Some other herbs may be mentioned : Thus, O'Brien & Naughton 

 (1928) found the fungus in localized patches of inner cortex in 

 Fragaria; and Treub (1885) said that in Sacchariim the central 

 cylinder is never invaded. For the ferns the same condition obtains : 

 In the sporophyte of Botrychium, at a definite distance from the 

 epidermis, the fungus branches copiously and forms sporangioles 

 while the vascular tissue is free. In the gametophyte the outer cells 

 are at first invaded but become fungus-free, which is the condition 

 of the apex and reproductive organs at all times. In Ophioglossum 

 prothalli the inner cells are fungus-infested while the outer are free 

 (Bruchmann, 1904; Lang, 1902). In Lycopodium the fungus is 

 present in epidermis of prothallus only (Hollo way, 1920), or at 

 most 1-2 outer cell layers (Goebel, 1887). 



Supposed limitation of endophytic invasion by what are called 

 tannin deposits does not occur, for the endophyte can freely invade 

 such cells. Incidentally it may be remarked that Woodroof (1933) 

 found tannin formed in cold weather and present in both mycor- 

 rhizal and non-mycorrhizal roots.* 



Limitation in Hepatics : — Every report on the hepatics indicates 

 a definite localization of the endophyte. Thus, in Conocephalus the 

 fungus is limited to a zone of central tissue (Beauverie, 1902), while 

 GoLENKiN (1902) reports that in a number of liverworts the hyphae 

 are confined to a compact ventral tissue. In the New Zealand liverwort 

 Monoclea the fungus is found in a sharply defined zone and does not 

 occur in the growing point (Cavers, 1903). In Marchantia the fungus 

 is limited to a zone beneath the air cavities (Chaudhuri, 1925), while 

 in Lumdaria the endophyte is present in a band of tissue (Emberger, 

 1924; Nicolas, 1924) along the midrib (Ridler, 1923). Ridler 



*MacDougal & DuFRENOY State that decompensated respiration results in 

 polymerization of the quinoids into gummy masses, the presence of which forms 

 a barrier to tlie extension of hyphae (Plant Physiol. 21 :1-10, 1946). 



