118 
G. F. Atkinson, 
growth of the veil primordium takes place providing for the amount of 
material present in the veil and annulus of the mature plant. Figs. 5 
and 6 represent the dense layer of palisade hyphae of the hymenophore 
primordium many of which are still slender and pointed below, the layer 
in section appearing in the form of an arch above the gill cavity. Because 
of the rich protoplasmic content of these hyphae the young hymenophore 
is deeply stained and in strong contrast with the adjacent tissue. The 
cortical tissue just beneath the zone of radial hyphae is becoming more 
active and also begins to stain more deeply, quite as much so or a little 
more strongly than the radial hyphae of the outer zone. In more advanced 
stages it is very distinct showing clearly its differentiation into the cortex 
or outer portion of the pileus. 
This is interesting as indicating that the tissue, which ultimately 
gives rise by growth and increase to the cortex of the pileus, is recogni¬ 
zable in a primordial condition at a very young stage of the carpophore, 
as a middle zone of tissue before the differentiation of pileus and stem 
primordia. There is some question as to the homology of these two 
outer zones in the young fruit body, i. e., the zone of radial hyphae and 
the irregular zone of pseudoparenchymatous tissue here spoken of as a 
cortex. The two zones seem to be homologous with two similar zones 
much better differentiated in the young carpophores of Lepiota clypeolaria 
which will be fully described in another paper. This much may be said 
here, however, that there is evidence in L. clypeolaria of the homology 
of these two outer zones with the volva or “universal veil” in certain 
species of Amanita and Amanitopsis. But in certain species of the 
latter genera the “universal veil” becomes clearly separated as a volva by 
a method which I shall describe in another forthcoming paper on Ama¬ 
nitopsis vaginata. In Lepiota the universal veil is “concrete with the 
epidermis of the pileus”, and it would appear that a simular situation 
exists in Armillaria mellea . In this connection a study of the development 
of Armillaria imperialis Fries would be extremely interesting. From 
what I have observed in the development of the later stages of this plant, 
from material collected in the Jura Mountains of France at Boujeailles 
near Pontarlier, in August, 1905, it appears that the univeral veil, in 
part at least, separates distinctly from the surface of the pileus and forms 
the lower ring on the stem, this species being said to possess a duplex 
annulus 1 ). It is interesting that certain species of two different genera 
possess an outer zone of radial hyphae arising from a zone of cortical 
tissue, but the radial hyphae in Armillaria mellea do not form so com¬ 
pact a zone as in Lepiota clypeolaria. 
Although the primordium of the pileus is not well seen at the time 
of the origin of the hymenophore primordium, the latter indicates the 
beginning of the differentiation of the young carpophore into the pileus 
and stem portions. The epinasty of the threads which form the hymeno¬ 
phore primordium, as well as of the superficial threads which assist in 
forming the veil, is an indication that the pileus is being organized, since 
the epinastic growth is one of the special peculiarities of the pileus in 
its early stages of growth, especially the marginal portions of the pileus. 
At the very earliest beginning, however, of the differentiation in the region 
1) Fries, E.. leones Hym. 18, pi. 17, 1867. — Gillet, C. C., Champ. 
France, 78, fig. opposite p. 73, 1878. — Saccardo, P. A., Syll. Fung. 5, 79, 1887. 
