70 
Mycologia 
Lanzi. Pilosace algeriensis appears to be very rare in Europe. 
Prof. i\Iaire informs me he has never seen the species. 
In addition to -what has been said about the species by Peck, 
Atkinson, McKenna, Miss Sherman, and in my former article, 
some points regarding the effect of the parasite on the host plant 
are shown in these illustrations. 
The carpophores of the parasite grow from the center of the 
pileus of the host either singly or in clusters. A comparison with 
the normal forms of the host, pi. i/Q,f. C, D, shows that the para- 
site has prevented the natural elongation of the stem. In very 
young carpophores of Coprinus, before the stem has begun to 
elongate, the gill chambers open outward and more or less down- 
ward with their bases and outer ends in the substance of the 
pileus, and their inner ends in that of the stem, although the exact 
point where the stem ends and the pileus begins, is somewhat 
arbitrary at this early stage of development. The mouths of the 
chambers are closed by the tissue of the veil, which is continuous 
with the trama of the gills. This is seen in Levine’s figures of the 
young stages of Coprinus micaceiis, Amer. Jour. Bot. i : pi. jp, /. 
13-14 and pi. 40, f. p. I have no photographs of the young stages 
of Coprinus, but the sections of Agaricus arvensis, pi. lyp, f. E, F, 
are similar in the position of the young gill chambers. In /. E, 
the chambers point diagonally upward. Compare Atkinson’s 
illustrations in the Amer. Jour. Bot. i : pi. i. 
In normal non-parasitized plants of Coprinus atramentarius, 
the elongation of the stem and the simultaneous epinastic growth 
in the pileus results in a reversed position of the gill chambers so 
that when the pileus is formed and ready to expand the chambers 
lie in a vertical position with their bases outward and their edges 
towards the stem as in /. D. In plants which are parasitized, the 
elongation of the stem is inhibited and the enlarged gill chambers 
still lie obliquely upward with their mouths outward in the posi- 
tion which they have in the fully expanded carpophore of a mush- 
room of which the pileus becomes obconic or infundibuliform. 
Thus is formed the top-shaped mass of the host plant shown in 
the illustrations. 
The substance of the veil which is left near the base of the 
stem in normal plants, pi. ipp, f. C, becomes greatly thickened and 
