Notes and Brief Articles 
185 
divides. Kniep holds that the clamp is budded from the mycelial 
cell at some point between the two nuclei. So soon as the clamp 
is sufficiently large one of the nuclei moves into it while the other 
comes to lie near its base. Conjugate division of the nuclei now 
takes place. The daughter nuclei arrange themselves so that two 
non-sister nuclei move to the apical portion of the cell, one re- 
mains in the basal portion while the fourth is left in the clamp 
connection. Kniep finds that the cross wall of the mother cell 
does not appear until after the clamp has budded out and that it is 
formed directly below the origin of the clamp connection. Later 
a second wall appears at the base of the clamp separating it from 
the apical cell. The result of these processes is a binucleated 
apical cell, a uninucleated basal cell, and the clamp with a small 
nucleus. Fusion of the basal cell and the clamp connection now 
takes place and the nucleus of the clamp connection passes into 
the basal cell. Thus making the basal cell also binucleated. 
When a branch is formed, practically the same sequence of 
phenomena occurs. One nucleus remains in the mother cell, the 
other migrates to the new branch and a clamp connection is 
formed between them. In old mycelial cells fusion of the clamp 
connection and the basal cell takes place quite regularly. Kniep 
found this peculiar type of conjugate division also in Panus stip- 
ticus, Clitocybe flaccida, and Polyporus destructor, but unfortu- 
nately he gives no figures in spite of the fact that these forms have 
been studied by other cytologists who failed to find such divisions. 
Kniep also takes up the question of the phylogenetic significance 
of the clamp connection. Kniep claims that the binucleated my- 
celial cells are the homologues of the ascogenous hyphae. He 
also contends that the penultimate cell of the ascogenous hyphae 
is the homologue of the apical mycelial cell, and the clamp con- 
nection is the homologue of the end cell in an ascogenous hypha. 
The question that naturally suggests itself is: Does the apical 
mycelial cell of the Basidiomycetes become the basidium as the 
penultimate cell becomes the ascus in the Ascomycetes? Kniep 
claims to have traced the hyphae in a number of forms and found 
that there is a clamp connection between every two adjacent 
binucleated cells and there is likewise a clamp connection at the 
base of each basidium. But in Lactarius piperatus Scop., Tricho- 
