POLYPORUS FERRUGINOSUS. RUST-COLOURED
POLYPORUS.
POLYPORUS ferruginosus; resupinatus ferrugineus arachnoideo-filamentosus demum lateralis ses-
silis, pileo convexo tenui subtomentosus, poris profundis majusculis insequalibus an-
gulatis.
POLYPORUS ferruginosus. Fries Syst. Mycol. vol. 1. p. 378.
BOLETUS ferruginosus. Pers. Syn. Fung. p. 544.
BOLETUS resupinatus. Bolt. Fung. vol. 2. t. 213 ?
BOLETUS Cryptarum. Bull. Fung. t. 478 ?
C lass a n d O r d e r . CRYPTOGAMIA FUNGI.
[ N a t u r a l O r d e r . F U N G I , Juss., Decand., Hook.J
G e n . C h a r . Hymenium cum pilei substantia homogeneum et concretum; poris subrotundis, dissepimentis te-
nuibus simplicibus instructum. Pileus subcarnosus vel suberosus, plerumque subsessilis, substantia fibrosa,
sicca. Velum nullum. Grev.
G e n . C i ia r . Hymenium (o r fructifying portion) o f the
furnished with pores o f which th e dissepiments a re th
rally subsessile; th e substance fibrous an d dry.
F un g u s hie singularis primum effusus est, e t omnino e
filamentis numerosis ochraceo-feiTugineis te-
nuissimis articulatis, Confervam simulantibus,for-
matus. Cito pulverulentus evadit, demum spon-
giosus.' e t in centre po ro su s; margines reflexi
sunt, e t Boletus m a turus la tera lite r affixus.
I n hoc sta tu P il e u s tenuis est, subhemisphasricus, par-
vus, convexus, subtomentosus, ferrugineus, mar-
ginibus incurvis saturatioribusi
P o r i vel T u b i numerosi, semiunciatfi e t u ltra longi, irreguläres,
angulati, pallide ferruginei, sub summo
len te evidenter e filamentis minutissimis sporulis
fuscis in te rmix e s compositi.
same substance as th e pileus an d inco rp o ra ted with it,
i an d simple. Pileus somewhat fleshy o r corky, gene-
This singular F un g u s is at first spreading, and altogether
formed of numerous ochraceo-ferruginous
very slender jointed filaments which resemble a
Conferva. Soon it becomes pulverulent, then
spongy and porous in the centre; the margins
are reflexed, and the mature Boletus becomes
fixed on its side.
In this state the P il e u s is thin,subhemispherical, small,
convex, subtomentose, ferruginous, with the mar-
gins incurv'ed and of a deeper colour.
T h e P or e s o r T u b e s a re numerous, h a lf an inch a n d
more long, irregular, angled, pale ferruginous, an d
under a lens evidently o f very minute filaments
mixed with brown sporules.
Fig. 1. 2. Mature plants. Fig. 3. Plant in its young state ; all natural size. Fig. 4. Tubes of a mature plant.
Fig. 5. Part of a young plant, showing the web-like appearance and commencement of the tubes. Fig. 6. The
arachnoid filaments of a very young plant (before the commencement of the tubes is visible). Fig. 7. Substance
of the parietes or walls of the mature tubes, with the sporules :— allfromfigure 3. much magnified.
In a botanical excursion which Mr. Greville made in the vicinity of Edinburgh, with the view of searching for
Fungi to illustrate his valuable publication on that tribe, he was so fortunate as to meet with the subject of the
present plate, growing on decayed sticks and leaves in a wood at Braid Hermitage, where, extending from the
underside of a dead branch to which it was originally attached, it spread itself over the moss and grass which were
contiguous. I t appears, as far as we can judge from the imperfect figures and descriptions of this genus, to be a
species hitherto but imperfectly known to authors. But even if this claim to our notice be not admitted, there is so
much of curious in its development and structure, as pointed out to me by Mr. Greville,'that I am anxious to call
to it the attention of Botanists, in the hope that it may lead to a more intimate knowledge of the internal organization
of these plants-; and this I shall do in that gentleman’s own words:—
“ The first appearance of this vegetable is in the form of a most delicate ochreous brown web, finer even in texture
than that of the spider, and of so delicate a nature that the slightest touch is sufficient to injure it in its recent
state. This web, which has the strongest resemblance to a minute Conferva, becomes in the course of a few' days1
darker in the centre, and, gradually condensing in its substance, assumes a pulverulent aspect: its surface then is
seen to be irregularly pitted, the distance between the pits being extremely unequal: they approximate however by
degrees, and at the same time growing deeper, they change into pores or tubes; when, the plant being perfect,
it has reached to its maximum o f density. If, in this states the tubes be carefully broken down under a high
power of the microscope, they are found to consist of a condensed mass of slender filaments, similar in every respect
to those which form the plant in its young state, and intermixed with a profusion of sporules.
In the examination of the early filaments, they are seen so exactly to resemble a Conferva, that any botanist might
be pardoned for considering them as belonging to that genus. They are either jointed, or contain dark bodies
that may easily be taken for joints, and are attenuated at their extremity. No sporules are perceived until the
tubes begin to form, when they appear in great abundance, even before the tubes have attained to their full size.
I do not conceive the conjecture to be an improbable one, that the sporules are contained within these filaments
: in the old tubes, the latter are apparently somewhat disorganized, easily broken, and more colourless than
in their younger form, as if their contents had escaped : besides, the sporules never exceed in size the diameter of
the filaments?’
The Boletus resupinatus of Bolton (Boletus Cryptarum of Bulliard) has some affinity with the present indivi
dual: but its pores are described as exceedingly minute, scarcely visible to the naked eye; and no notice is taken
of the filarpentose origin of the plant, although the former author appears to have seen it in all its various stages
of growth.
For the beautiful drawing here engraved, as well as for the above details, I am indebted to the kindness of
Mr. Greville.