186 
Mycologia 
loma imbricatum Quel., and Amanitopsis vaginata Roze, no such 
clamp connections appear. According to Harper (Bot. Gaz. 
1902), there are no clamp connections between the basidia and the 
subhymenial cells in Hypochnus siibfilis and Coprinus ephemerus. 
Buller (Researches on Fungi, 1909) figures no clamps at the 
bases of the basidia in a number of Coprinus species. My own 
studies on Coprinus micaceus, C. ephemerus^ and C. stercorarius 
(unpublished) fail to show clamp connections on the basidia of 
these forms. In over twenty species of Boleti (Bull. Torr. Club, 
1913) no clamp connections were observed on the basidia. Yates’s 
figures of his histological studies of certain Boletaceae (Univ. 
Calif. Publ. 1916) also show no clamp connections. 
Kniep fails to trace the hyphae in the trama and to tell definitely 
whether or not he found clamp connections in these hyphae. 
Kniep’s theory of the clamp cell is not supported by sufficient evi- 
dence and it still remains to trace out the origin and the history 
of the binucleated hyphae through to the basidia. This un- 
doubtedly will clear up many questions on the morphology of the 
higher Basidiomycetes. Michael Levine. 
A Very Dangerous Mushroom 
The poisonous mushroom described below was brought to me 
for critical examination on May i, 1916, by Mrs. Rufus Hatch, 
of Pelham Manor, New York. It grew plentifully in her mush- 
room beds the past winter, almost to the exclusion of the com- 
mon cultivated mushroom, and was eaten by Mrs. Hatch and 
four members of her household with nearly fatal results. A full 
description of the effects will be published; but it is considered 
important to send out a warning immediately that poisonous 
mushrooms may apparently develop from commercial spazvn and 
that grozvers must be careful to eat or sell from their mushroom 
beds only the common mushroom zvith zvhite cap and pink gills, 
Agaricus campester. 
Panaeolus venenosus sp. nov. 
Pileus thick, fleshy, hemispheric when very young, sometimes 
hatshaped, at length expanded, cespitose, 3-5 cm. broad ; surface 
