ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 333 



of ferns belongino; to tlie Marattiaceae, Angiopteris, Kaiilfussia, etc, 

 Cyril West has now made a thoronsrh examination of the roots of 

 Angiopteris evecta, Archangiopteris Henryi, Kaulfussia aescalifolia and 

 Marattia Gooperi. In all of them he found a similar type of endophytic 

 funo'us. It enters the root through any of the epidermal cells in spite 

 of the cuticularization of the outer wall of these cells ; it is both inter- 

 and intra-cellular within the tissues of the host (mostly intercellular in 

 the inner cortical layers), and the filaments show few septa. The 

 secretion of enzymes is probably confined to the tips. From the inter- 

 cellular hyphse branches pierce the neighbouring cells and form 

 arbuscules within them, but in time these become disorganized and 

 probably are utilized as food to some extent by the host-cell, which 

 remains healthy. Mycelium is invariably absent from the tannin cells 

 and outside the ring of mucilage canals. Vesicles are formed at the 

 tips of the hyphal branches, which West regards as reserve bodies. In 

 addition spores are formed either intercalary or terminal ; they possess 

 a thin smooth exospore and a thick yellow mesopore layer or middle 

 wall, and are three to four times wider than the hyphte which give rise 

 to them. These spores were frequently found lying free in the tissues 

 of the host, but there was never any evidence of germination, and it is 

 concluded that they do not germinate till they reach the soil by decay 

 of the roots. The lack of suitable living material prevented further 

 examinations by cultures. 



West considers that the fungus most nearly approaches the genus 

 Phytophthora, and he has named it Stigeosporiwn Maratliacearum 

 g. et sp. n. 



He also investigated the mycorrhiza of Dansea alata and D. nodosa 

 which was distinct from Stigeosporium ; no reproductive bodies were 

 found. West has discussed the relationship between the host and the 

 fungus. He does not find that the fungus contributes any material 

 from the soil, and evidence is lacking as to the fixing of free nitrogen. 

 The host to a slight extent uses up the disorganized arbuscules. 



On the other hand, while the fungus does no damage to the host, it 

 yet lives on the host products as starch invariably disappears from the 

 invaded cells ; the resting spores of the fungus with their oily contents 

 are formed at the expense of the higher plant, hence the advantage of 

 the association is almost entirely on the side of the fungus. 



Endotrophic Mycorrhiza.* — M. C. Rayner has published a review of 

 recent research on endotrophic mycorrhiza. She gives a short historical 

 sketch of the progress of investigation from the time of Frank onwards. 

 She dwells on the experiments and discoveries by Bernard and Burgeff ; 

 the former proved convincingly the obligate character of symbiosis 

 between the orchid seed and the fungus, without which no germination 

 took place. Burgeff confirmed Bernard's work ; he suggested the name 

 Orcheomyces for these orchid fungi, and he succeeded in growing the 

 fungus of one orchid for twenty-six months on artificial media. 



* New Phytologist, xv. (1916) pp. 161-75. 



