138 LEVINE: CYTOLOGY oF HYMENOMYCETES 
first the so-called clamp connections and second, the ordinary 
hyphal anastomoses. Such fusions are, however, well known in 
other groups of fungi with normal sexual reproduction and the 
possibility that they may have sexual significance in the Basidio- - 
mycetes seems remote. 
Hoffman (1856) was the first to figure the clamp connections 
between hyphal cells. He clearly described the slender tube 
joining two adjacent cells just outside their common cross wall 
and gave the name ‘‘Schnallenzellen”’ or clamp connections to 
these delicate structures. Brefeld emphasized the fact that 
clamp connections are not permanently open, for shortly after 
the tube buds out, a wall appears cutting it off from the cell from 
which it arose. Eventually, he claims, a second wall is formed 
separating the clamps entirely from each of the cells which it 
joins. The cell which puts out the clamp connection is always 
the one on the apical side of the transverse wall. Harper (1902) 
does not agree with Brefeld on the point that the fusion tube is 
cut off from both cells which it joins and interprets the clamps 
as a means of interchange of food stuffs. 
Lyman (1907) finds clamp connections arising very early. 
In one species, Corticium roseo-pallens, clamp connections are 
found in the germ tubes, while in Corticium subgiganteum no 
clamps at all are produced. Lyman studied artificial cultures of 
75 species of Thelephoraceae, Hydnaceae, and Polyporaceae and 
finds accessory reproductive bodies, such as oidia in Daedalea 
unicolor, Lenzites betulina, Polyporus fumosus, Polystictus conchifer, 
Polystictus versicolor, and in Corticium alutaceum; and chlamy- 
dospores in Lentodium squamulosum, Poria incrustans, Radulum 
tomentosum, two species of Hydnum and one of Phlebia, Corticiwm 
vagum, C. effuscatum, and Michenera artocreas. Bulbils composed of 
a mass of hyphae were found in cultures of Corticium alutaceum. 
It would be extremely interesting, in view of the early origin of 
binucleated cells in the mycelium of many species, to know the 
number of nuclei in each of these types of asexual spores as af 
indication of whether they are to be reckoned with the gameto- 
phyte or sporophyte generation. 
It has been the common view that clamp connections and 
hyphal anastomoses have to do with food transportation etc. 
