MR. W. PHILLIPS ON THE GENUS VIBRISSEA. 3 
kind of thin subiculum, not much unlike what is found under Peziza fusca (РІ. I. fig. 1). 
This is the mycelium. Repeated examinations of the tissue of the wood failed to show | 
that this mycelium had penetrated to any depth ; it rather lay upon the surface, or at 
most only entered into the disintegrated portion. "The wood immediately beneath was 
perfectly firm and uninjured. The mycelial threads are about "005 millim. in diameter. 
Vibrissea Guernisaci has a mycelium in all respects similar to the above, though not so 
abundant. 
The Stipes.—The first indication of a young plant of Vibrissea truncorum is the forma- 
tion, by the mycelium, of a minute conical protuberance just visible by the aid of a 
pocket lens. If one of these be examined by making a vertical section when about half 
a millimetre high, it will be seen to consist of two distinct tissues—the one external, the 
other internal. The external tissue (cortical tissue) is composed of a thin compacted 
stratum of blackish threads, running nearly parallel to each other, of the same size as 
those of the mycelium, and in all respects similar to them. Within this is a pale nucleus 
(the internal tissue, medullary tissue), composed of nearly colourless parallel threads 
of a less diameter than those forming the exterior tissue. When viewed in mass this 
medullary tissue is of а pale cinereous colour. In this early stage of an individual plant 
we see present the two tissues which form the stipes of the mature plant, whether it be 
long or short. In the sessile species they are equally present. 
The stem of V. truncorum varies from 2 to 6 lines long, and is barely a line thick, 
often enlarged at the top; the texture is tough ; and the colour is pale glaucous in the 
upper part, darker below ; and it is minutely squamulose. The squamul are produced by 
the cells of the cortical tissue projecting from the surface as dark septate short hairs. In 
Vibrissea margarita, White, these hairs are more conspicuous and prominent, extending 
up the whole of the stipes even to the margin of the receptacle, which gives this species 
its distinguishing character. In old specimens the stipes of both becomes partially 
hollow. 
The Hymenium.—W hen а plant of Vibrissea truncorum is approaching its maturity the 
hitherto cylindrical stem begins to enlarge at the summit, and the cortical tissue opens 
at a point in the centre, through which the paler medullary tissue may be seen forcing 
its way to the light, preparing to give rise to the hymenium. "The hymenium owes its 
origin to the medullary tissue by the formation of a thin subhymenial tissue, somewhat 
closer and more compact, from which the asci and paraphyses immediately arise. In the 
earliest stage of its existence the hymenium consists of a bed of upright, closely adjacent, 
slender threads, destined to become the asci and paraphyses. It is impossible at this 
stage to say which of these threads will be asci and which paraphyses ; for they are in all 
points alike. They are elongated cells filled with a transparent protoplasm in the form - 
of minute granules. The first differentiation that can be observed in these threads is 
that some of them throw out lateral branches, which proves they are paraphyses ; for the 
asci are never branched. At а more advanced stage others of these threads increase іп 
diameter from Ше summit to near their base, and the protoplasm they contain arranges - 
itself in parallel lines, but having a waved appearance: these are the asci. On further 
approaching maturity this waved appearance disappears, and the protoplasm resolves 
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