British Gastromycetes. 23 
and Gautieria the basidia are irregular in form and produce a 
variable number of spores, as is usual in most of the Hymeno- 
gastreae. Berkeley considers Gautieria as belonging to the 
Clavarieae, and nearest to Sparassis , which is often so much 
curled that the normal sporiferous external surface becomes 
in some parts converted into sinuous closed cavities. Evidence 
of affinity derived from the general structure and habit of the 
sporophore is stated by De Bary as follows : ‘ If we could 
attribute a decisive value to the habit of the plants we should 
dwell upon the great resemblance between the stalked Hymeno- 
gastreae, like Secotium erythrocephalum and a veiled Boletus , or 
still more perhaps that of Polyplocium to the same species, 
though Polyplocium is too little known in its earlier states. 
But among the Polyporeae there is a remarkable form, Polyporus 
volvatus , Pk., the Polyporus obvallatus of Berk, and Cooke, 
which considered by itself must be placed with, or close to, the 
Hymenogastreae. Its sporophore which lives in the bark of 
trees, is a hollow spherical body flattened at the poles, and 
about the size of a hazel-nut, with a thick closed wall of 
leathery texture ; its interior surface is covered with the 
hymenium of a Polyporus on the part next the substratum 
and is sterile on the opposite side V With regard to the 
above description, De Bary must have been misled by the 
examination of a very young and imperfect specimen, and has 
evidently mistaken the apex for the base. The species has 
been very fully described and figured by Peck 2 , who states that 
it is gregarious in habit, growing on the dead trunks of Abies 
nigra and one or two other coniferous trees, not in the bark 
but laterally from it, and is often furnished with a short stem. 
The stratum of pores, 4-5 mm. long, and very uniform, ori- 
ginates from the underside of the lateral pileus, the most 
remarkable peculiarity being the prolongation of the margin 
of the pileus which extends beyond the pores and becomes 
curved under, at first concealing the hymenium. ‘ In two of 
1 1. c. 337. 
2 Polyporus volvatus, Peck, and its varieties, Bull. Torr. Bot. Club, vol. vi. 
n. io, p. 102. 
