343 
and its Mycorhiza. 
keulige Auftreibungen, die auf den ersten Blick wie begin - 
nende Sporenbildungen aussahen. Dlese Gebilde traten auch 
kettenformlg hinter elnander auf, waren reicher an Proto- 
plasma als die Fadentheile und besassen grosse Vacuolen. 
In der Kultur wuchsen sie wieder zu gewohnlichen Faden 
aus, ohne sich zu Reproductionsorganen auszubilden.’ 
W. Wahrlich 1 Investigated other Orchids, and the first stage 
he found in the cortical parenchyma of the fungal clumps was 
a sac-like swelling of a hypha which soon gave off numerous 
branches. These latter finally form a close system of fine 
hyphae concealing the original sac. Kuhn 2 showed that in 
the mycorhiza of Marattiaceae mycelial clumps occur with 
a central bladder-like sac ; in fact are just like those described 
by Wahrlich. Kuhn figures a cell from the mycorhiza of 
Angiopteris evecta as containing a bladder, also a hypha 
dilating into a terminal spherical body which Is rich In 
protoplasm and possesses a large nucleus. This last he 
terms a spore with a large nucleus. But I have no doubt 
that the nucleus (as its size indicates) was really lying outside 
the spherical body and was the nucleus of the host-cell, and 
the sphere itself was nothing else than a young bladder. 
So It seems likely that in Angiopteris , too, the bladders form 
first In contact with the nucleus of the host-cell. 
B. Physiology. 
Discussion of the Behaviour of the Mycorhizal Mycelia. 
The first prominent fact with reference to the mycelia of 
Thismia is that a young hypha on entering a cell grows 
directly towards the nucleus of the latter. There are two 
possible explanations of this phenomenon. It may be that 
the hypha grows in that direction for purely mechanical 
1 W. Wahrlich, Beitrag zur Kenntniss der Orchideenwurzelpilze. Bot. Zeit. 
1 886, p. 480. 
2 R. Kuhn, U ntersuchungen iiber die Anatomic der Marattiaceae und anderer 
Gefasskryptogamen. Flora, 1889, PP- 49 I_ 497 * 
