There are several species of _Stereum_ in Britain, three species of which when handled in the fresh state stain red: _S. sanguinolentum_ (A. & S.) Fries, a pale coloured species on conifer wood, _S. rugosum_ (Pers.) Fries a similar coloured species on beech, birch and especially hazel, and _S. gausapatum_ Fries an ochraceous yellow species on oak, often forming a pocket rot of the timber. However, the commonest member of the genus is an orange-tawny coloured species with a greyish buff, hairy cap, _S. hirsutum_ (Willd) Fries. It grows on many trees of broad-leaved wood and can be found wherever twigs, branches, trunks or stumps have been lying out in the rain; it does not bleed. [Illustration: Plate 59. Resupinate fungi] Those species of resupinate fungi which resemble members of this genus, i.e. those with a distinct tough, although poorly developed, cap, are called stereoid. ‘Red thread disease’ of grass which often causes unsightly red patches on lawns and school and corporation playing-fields is caused by _Corticium fuciforme_ (Berkeley) Wakefield. Fungi belonging to this genus produce fruit-bodies which ‘scramble’ over the substrate; for example, if one searches old elder trees throughout the year one will certainly find a ‘white wash’ fungus of this type, _Hyphodontia sambuci_ (Pers.) J. Eriksson. Fungi with this type of fruit-body are called corticoid. The two major types are illustrated along with some of the bizarre microscopic structures one finds in the resupinates; such structures are useful in classification and identification, and their beauty and intricacy make up for the surprisingly simple fruit-body shape and texture. C. THE JELLY FUNGI _Key to the major groups_ The jelly fungi or Hymenomycetous heterobasidiae is a complex group of fungi and not only includes our common jelly fungi but many microscopic forms some of which are parasitic. The group is divided into three main divisions depending on the position of the cross-walls within the basidium, or whether the basidium is in the shape of a tuning-fork. They are probably not closely related one to another. =Auriculariales= (Basidia divided into cells by transverse walls) 1. Fruit-body lacking a cap and more or less forming a gelatinous coating on plant-debris _Helicobasidium_ Fruit-body with more or less distinct cap, gelatinous but tough 2 2. Fruit-body ear-like or cup-shaped; upper surface with grey hairs and lower surface lilaceous brown or wine-coloured _Hirneola_ Fruit-body at first cup-shaped but then spreading; upper surface grey and hairy, and lower surface purplish. _Auricularia_ =Tremellales= (Basidia divided into cells by longitudinal walls) 1. Fruit-body with distinct stem and spines on lower surface _Pseudohydnum_