108 Rhodora [JUNE 
HYDNUM CAPUT-MEDUSAE. 
HoLLis WEBSTER. 
Hydnum Caput-Medusae is a fungus apt to be conspicuous in the 
minds of those newly attracted to observe and collect our fleshy fungi. 
Its name has a definite suggestiveness, it belongs to a genus readily 
recognized, and it is pictured or described in popular accounts as 
such a remarkable and fascinating object that every true fungus-hunter 
longs to find it, photograph it, possess it, exhibit it, and even, it may 
be, to eat it. That such a desire (in which the writer may admit his 
share) is prevalent and determined, is evident from the numerous 
reports that go about every season of the finding of the Medusa 
hydnum, and from the frequent despatch to the centres of information 
of specimens so labeled. Unfortunately for the satisfaction of ardent 
collectors, it is only too probable that they are in most cases 
deceived ; ten to one, at least, they have something else. Hence, it 
is by way of warning against such a common mistake that attention is 
here called to certain other species which are the innocent cause of it. 
If the reader will turn to Stevenson’s British Fungi, or to 
Massee’s British Fungus Flora, he will find described along with this 
species, two others somewhat similar, Æ. coralloides (Coral hydnum) 
and 77. Erinaceus (Hedgehog hydnum), and if he will examine also 
plate seven of the first volume of Fries's Icones and the accompany- 
ing description (p. 9), he will learn details of a fourth species, Æ. 
Caput-ursi (Bear's-head hydnum) even more like his probable notion 
of H. Caput- Medusae. All of these four species are large, white, and 
provided abundantly with long fleshy spines, and all, except the Coral 
hydnum, generally have a firm, fleshy body. No exhaustive descrip- 
tion of them need be given here, it being the writer's intention mainly - 
to awaken, in the minds of uninformed readers, a feeling of uncer- 
tainty that will be banished only by a careful study of the details 
given in the references mentioned. Still, it may be well to point out 
that the Coral hydnum is fairly distinct by reason of its comparatively 
delicate branching habit. Of the others, the Hedgehog hydnum is not 
at all branched but is tuberculose and has very long spines, and is some- 
what lacerate fibrillose above; the Medusa hydnum is also unbranched, 
1 See also C. H. Peck, Report of the State Botanist of New York for 1897. Pp. 
310, 311, 
