_General Information_: The genus _Polyporus_ is in most text-books, a big and unwieldy genus joining together all fleshy, annual fungi possessing tubes; even the boleti (see p. 32) have been included! Many of these species are now considered less closely related one to another than previously thought. Boleti differ from polypores, however, in their less tough and distinctly putrescent fruit-body, and in the fact that the margin of the cap extends but does not continue to grow during the life-cycle; the margin of the polypore fruit-body is active and may burst into growth again when favourable weather conditions occur. The ‘Scaly polypore’ has a flesh which consists of two types of hyphae: (i) hyphae of unlimited growth with abundant protoplasmic contents which stain easily and which collapse on drying; and (ii) thick-walled, strengthening hyphae which bind the thin walled hyphae together. _Laetiporus sulphureus_ (Fries) Murrill ‘Sulphur polypore’ has a single type of hyphae in the tubes, i.e. thin walled generative, and only a few binding hyphae in the flesh. It has an orange cap with a rather thick, sulphur or chrome-yellow margin, sulphur-yellow tubes and pores and yellow, then pale buff, flesh. The spore-print is white and the spores hyaline, pip-shaped and medium sized, (5-7 × 4-5 µm). _Illustrations_: _P. squamosus_--F 43^{b}; Hvass 267; LH 75; NB 129¹; WD 94¹. _L. sulphureus_--Hvass 268; LH 73; NB 129³; WD 94². [Illustration: Plate 44. Woody fungi: Spores white and borne within tubes--fruit-body annual] Some common annual polypores ~Piptoporus betulinus~ (Fries) Karsten Birch polypore Cap: 75-200 mm, kidney-shaped or hoof-shaped, smooth, covered by a thin, separable and greyish silvery or pale brownish skin; cap-margin thick, incurved and projects beyond the tubes. Stem: rudimentary, simply a small hump below which the fungus develops. Tubes, pores and spore-print: white. Spores: sausage-shaped, and thin-walled hyaline under the microscope and very narrow, (5-6 × 1-2 µm). It grows on birch throughout the country where it causes a sap wood-rot which finally converts the inner timber to a red-brown friable mass. The flesh, which contains thickened binding hyphae, is used for mounting insects and for sharpening knives, hence the common name ‘Razor-strop fungus’. _Illustrations_: Hvass 269; LH 67; NB 117⁴; WD 93³. ~Inonotus hispidus~ (Fries) Karsten Shaggy polypore Cap: 100-250 mm, kidney-shaped, yellow-brown to rust-brown, but finally almost black, at first covered with shaggy hairs, but these tend to mat together with age. Stem: absent. Tubes and flesh: rust-colour; pores at first yellow, but finally red-brown. Spore-print: yellow-brown.