18 
ON PENIOrHORA. 
The hymenium of some species of the genus Stereum of Fries, 
is so decidedly velvety, that he could scarce do other than associate 
them in a group or subgenus whilst he ignored the generic value 
of Hymenochcete , as applied to this group by Leveille. 
In the “ Annales des Sciences Naturelles,” for 1846, Dr. 
Leveille proposed Hymenochcete as a genus in which he included 
certain species of Thelepliora , Stereum, and Corticium, which had 
the hymenium studded with persistent rigid setae. These he further 
described as simple elongated cells, having the form of little cones, 
hearing no resemblance whatever to basidia. In our own country, 
the Rev. M. J. Berkeley accepted this genus as one worthy of 
adoption, as did also some Continental mycologists, whilst others 
still reject it, without any good or substantial reason. It is certain 
that the character is a permanent one, and that, as far as our ex- 
perience goes, is confined to the species in which it is habitually 
present. This appears to be a good and valid reason in its favour, 
but beyond this, and confirmatory of it, is the fact that there is a 
general natural affinity and harmony of the species, so that almost 
at a glance one is led to attribute a new or unknown species to this 
genus on the faith of general appearance. 
In the species of Stereum the hymenium (except in these ex- 
cluded species), is smooth, composed of basidia compactly arranged 
side by side, and of uniform height. There are no other cells 
present, except in one or two isolated cases, to be alluded to here- 
after, and certainly no indication of suppressed or undeveloped 
setae, as in Hymenochcete. 
If, on the other hand, a section be cut through the hymenium of 
such a species as Hymenochcete ruhiginosa, Lev. (Sterium rubigino- 
sum , Fr.), elongated bright-brown setae will be seen arising from 
the same stratum as the basidia, passing between them and rising 
above the surface, to a height at least equal to three or four times 
the length of the basidia. These setae are simple cells, without 
any indication of septa, gradually attenuated upwards, and with 
the external surface entirely smooth. 
In some species, as in Hymenochcete ruhiginosa , the setae are 
uniformly long and slender, whereas in others, as in Hymenochcete 
tabacina , Lev., they are shorter and thicker, and in Hymenochcete 
pellicula , Berk. & Br., very small and delicate, but in all the 
character is the same, though differing in size and proportions. 
This much is known to all mycologists, and admitted even by 
those who will not accept Leveille’s genus, against which no sound 
objection has yet been urged. There is nevertheless another form 
of hymenium which prevails in some species of Corticium and in 
one or two species of Stereum , which, if known, is not recognised. 
This form seems to bear just the same relationship to Corticium 
that Hymenochcete bears to Stereum. It may be illustrated by a 
very common and familiar species. 
If a section be cut through the hymenium of Corticium querci- 
num, Fr., it will be seen that there are numerous bodies mixed 
