The genus _Collybia_ is characterised by the fruit-body being tough, the cap-margin incurved at first and the spore-print white or whitish. The common fungus _C. maculata_ has always been assumed to have a white spore-print but if a cap is placed on a piece of white paper gills-down and left for twelve hours there is a surprise in store for the careful observer. _Illustrations_: F 15a; Hvass 77; LH 101; NB 103⁴; WD 21². [Illustration: Plate 24. Fleshy fungi with tough stem: Spores white to cream and borne on gills] The specialised substrates of certain species of _Marasmius_ and related genera A whole series of very small fungi are found in woodland communities which appear to be closely related one to another because their caps are usually tough, although membranous, dry rapidly yet do not decay, and, moreover, revive on remoistening. Their gills are also rather tough and their spores always white in mass. They are placed in the genus _Marasmius_. _Collybia_ or _Marasmius peronatus_ (Fries) Fries the ‘wood woolly foot’ is one of our larger more familiar agarics related to this group, but whereas it grows on all kinds of leafy detritus, even wood, these small fungi appear to be very specific to the substrate on which they grow. ~M. androsaceus~ (Fries) Fries grows both on heather and on pine-needles (see p. 231). Cap: whitish or pinkish buff. Stem: black and hair-like. Spores: pip-shaped and 7-9 × 3-4 µm. ~M. buxi~ Fries grows on box leaves. ~M. epiphylloides~ (Rea) Saccardo & Trotter grows on ivy leaves. ~M. graminum~ (Libert) Berkeley grows on grass stems. Cap: red-brown. Stem: dark brown. Spores: pip-shaped, 8-12 × 4-6 µm. ~M. hudsonii~ (Fries) Fries grows on holly leaves. ~M. perforans~ (Fries) Fries grows on pine needles (now placed in the genus _Micromphale_). ~M. undatus~ (Berkeley) Fries grows on bracken stems. Cap: reddish brown or greyish and wrinkled. Spores: egg-shaped, 8-9 × 6-7 µm. Except for their rather special requirements as to substrate preference, these species have in common small size, rather tough horny stems and cap composed of erect ornamented cells. Several agarics which grow on cones have also been placed in _Marasmius_. They are frequent in spring and early summer the fruit-bodies being attached by a very long rooting stem and cord of fluffy hyphae to buried cones in conifers. The biology of these fungi is still unknown, but the cones to which they are attached are always closed yet buried often several inches beneath the surface of the soil. It is yet to be found whether the spores of the agaric infect the cones after they drop or whether the cones fall because they have become infected. How do the cones become so deeply buried? Are squirrels or rodents involved? All the species which grow on cones have brown or tawny caps and yellowish brown stems.