Lecture VII — 93 — Mycothalli and Mycorrhizomes 



thalli the fungus is localized in cells throughout the thallus. Sterile 

 thalli were destitute of mycelium and Nicolas thought that presence 

 of fungus is necessary to fructification. 



Emberger (1924) also found hyphae in Lumdaria cruciata oc- 

 cupying a large band separated from the lower surface by several 

 layers of cells ; the chloroplast tissue is never invaded. Inconstancy of 

 infection, he thought, negated the hypothesis that infection is neces- 

 sary to formation of sexual organs ; and the association seemed simply 

 accidental. It was supposed by Ncmec (1899) that mycothalli are 

 general in Jungermanniaceae but rare or absent from Marchantiaceae. 

 We have already seen that infection is common in Lumdaria; it also 

 occurs in Marchantia and a number of other European hepatics ac- 

 cording to GoLENKiN (1902), who found that in all cases the fungal 

 hyphae are confined to the compact ventral tissue ; and infected cells, 

 though they retain nuclei and protoplasm, never contain starch or 

 chlorophyll. Thalli of Marchantia nepalensis on sand and clay at 

 Lahore, India, contained a fungus limited to a zone beneath the air 

 cavities, and branched and interwoven in the cells (Chaudhuri, 

 1925). Chlamydospores were sometimes found. In this and other 

 Indian liverworts, infection is localized in regions definite for each 

 species (Chaudhuri, 1935). Conocephalus is similar to the preced- 

 ing, as described by Bolleter (1905) who found the thalli often 

 turned red upon infection; but in alpine situations the thalli turned 

 red without infection, — another fact in line with Costantin & 

 Magrou's idea that refrigeration parallels the action of mycotrophy. 



Digestion of Endophyte: — In his description of mycothallism 

 in Pellia, Magrou (1925) said that the fungus degenerates about the 

 archegonia or the sporogonia, which organs seem to exert an inhibitory 

 influence on its growth. The endophyte exhibits all the structures 

 characteristic of mycorrhizal fungi, — large non-septate hyphae, ar- 

 buscles, sporangioles and multinucleate vesicles, the contents separat- 

 ing into uninucleate cells. Digestive structures were also described by 

 Garjeanne (1903) from thalli of Netherlands hverworts, — haustoria 

 and hyphal coils (Knauel) ; and under influence of the latter the 

 cells disorganized. Immersed clots were found in a number of liver- 

 worts by MiLDE (1851), while Ncmec (1904) found clots in Caly- 

 pogeia coincident with degeneration of mid-hyphae: they disappear 

 before death of the thallus. Many vesicles were formed in tissues of 

 Conocephalus but few in Lumdaria (Bergamaschi, 1932). Chalaud 

 (1932) figures vesicles and arbuscles in S ewardiella. 



Tuberous-thickening of the stem of Fossornhronia with which a 

 fungus was always associated was noted by Humphrey (1906) ; while 



