Lecture IX — 127 — Structure 



the plant plasm, as a clot (Klumpe) which is dead, unchangeable waste 

 product. On death of the fungus a copious formation of vacuoles 

 takes place and by union of vacuoles a large sap-vacuole is formed 

 in which the clot remains suspended. A new cell membrane may be 

 formed about this body: Thus are formed the clots, the "gelbliche 

 Stoffe", which puzzled earlier observers. 



BuRGEFF (1909) observed formation of hyphal coils external to 

 the mycorrhiza: The hyphae excrete a drop of water into which an 

 hyphal branch grows, and this branch, hindered by the outer surface 

 tension from growing out of the drop, is consequently rolled into a 

 spiral inside. Thus might form the coils (pelotons) of the mycorrhiza. 



Three sorts of orchid mycorrhizae were distinguished by Burgeff 

 {I.e.), viz. {!) Neottid (including most sorts) ; (2) Coralloid {Coral- 

 lorhisa and Epipogon) ; {2) Sporangiole (including a tropical genus 

 only). Later (1931) he also described vesicle formation which, how- 

 ever, is not common in orchids. 



Hypertrophy of the nucleus occurs during fungal digestion {cf. 

 Magnus, Arcularius). 



The peloton mycorrhizae, therefore, are characterized by intra- 

 cellular infection whereby hyphae coil within the cells to form "pelo- 

 tons" which are afterwards to be digested : vesicles and sporangioles 

 are rarely developed in this sort. 



Vesicular- Arbuscular Mycorrhizae: — The "phycomycete my- 

 corrhiza" is distinguished by possession of arbuscles and vesicles. 

 Neill (1944) records as a further distinctive feature a constant anas- 

 tamosis of the hyphae which sometimes results in formation of a closed 

 system of intercommunicating passages traversed by moving proto- 

 plasm. 



Vesicles were first recorded by Mollberg in 1884 {cf. Groom, 

 1894) but were described by Janse (1897) : *T give the name of 

 'vesicles' to the spherical or ovoid swellings which occupy extremities 

 of the hyphae. In the young state these organs contain only a small 

 amount of protoplasm and their cavity is occupied almost entirely 

 by large vacuoles. Little by little the quantity of protoplasm augments, 

 nutritive reserves accumulate and finally they are filled with a granu- 

 lar mass in which are mixed oily droplets. I have found analogous 

 bodies in a great number of plants. May they be compared to the 

 cysts which are present in other fungi, and a role in the asexual multi- 

 plication of the endophyte be attributed to them? I incline to that 

 belief." It may be noted that vesicular swellings were figured by 

 Frank (1879) in nodules of Orohiis while they were described still 

 earlier (1847) by Reissek for certain monocotyls and for Cochlearia. 



