37 ° 
Burt . — The Development of 
General Conclusions. 
Although the receptaculum and the gleba are both differen- 
tiated from the early sheaf-like head of medullary tissue,, still 
the pseudoparenchymatous walls of the former seem to have 
nothing more immediately in common with the hymenium 
either in origin or in mode of formation. There is no good 
reason for considering the two structures homologous. 
The steps by which the lower and lateral portions of the 
sheaf-like head — those portions bearing the future hymenium 
— lose their original direct connexion with the medullary 
bundle M and become split away, as it were, from the stipe 
from below, have no parallel in the Clathreae, and remind one 
rather of the changes that occur in the formation of the pileus 
in some of the Agaricineae. 
Medullary tissue gives rise to both the tissue of the 
chambers of the wall and to the pseudoparenchyma of its 
partition-walls, and one portion of a hypha may undergo the 
modification characteristic of a chamber, while another portion 
differentiates into pseudoparenchyma. In the Clathreae, as 
pointed out in my paper on Anthurus borealis ^ , cortical tissue 
continued upward from the mycelial strand forms the pseudo- 
parenchyma, while the tissue of the chambers is of medullary 
origin, and not connected with that of the partition-walls. 
Such fundamental differences must signify that the Phalleae 
and the Clathreae are not directly related ; although they 
may properly be regarded as two parallel series of forms, on 
account of their general features of resemblance in spore 
characters and external form. 
This investigation was carried on in the Cryptogamic Labora- 
tory of Harvard University in the winter of 1894-95, under 
the direction o.f Professor W. G. Farlow. I desire to express 
my sincere thanks to Professor Farlow, and also to Professor 
Thaxter, for helpful suggestion and criticism received in the 
1 A North American Anthurus— its Structure and Development. Memoirs of 
the Boston Society of Natural History, Vol. iii, No. XIV, 1894. 
