Facial cystidia: flask-shaped with contents which turn yellowish in solutions containing ammonia. _General Information_: This fungus which appears from early summer to late autumn is recognised by the almost uniform ochraceous colour with hint of olive and its habit of growing in troops. The word elongatum means elongated and refers to the shape of the stem which pushes up through the _Sphagnum_ and in order to disperse its spores it must elongate so that it just pushes up above the bog-surface. _H. polytrichi_ is closely related to _H. elongatum_ but has a paler cap and stem and it grows in moss, particularly _Polytrichum_ in woodlands; the spores of _H. polytrichi_ are paler, slightly narrower and slightly thinner, but they have a much more distinct germ-pore. Both the above species have been formerly placed in _Psilocybe_, but they are more correctly classified in _Hypholoma_ along with the sulphur-tuft fungus (see p. 64) because of the cortina-like veil and specialised facial cystidia. _Illustrations_: WD 78⁵. ~Tephrocybe palustris~ (Peck) Donk _Cap_: width 12-30 mm. _Stem_: width 3-5 mm; length 50-75 mm. _Description_: Plate 75. Cap: bell-shaped then plane-convex, but finally depressed at centre, watery buff to greyish with flush of ochre or smoky grey, striate to centre when moist, but drying out non-striate and uniformly ochraceous buff. Stem: thin, rather long, smooth, similarly coloured to the cap or paler, fragile and whitish woolly at the base. Gills: dirty whitish, adnate with a tooth and not very crowded. Flesh: thin, watery buff, drying out ochraceous and with a strong smell of new meal. Spore-print: white. Spores: medium sized, hyaline under the microscope, oval, not turning blue-grey in solutions of iodine, and 6-7 × 4-5 µm in size. Marginal and facial cystidia: absent. _General Information_: This fungus which grows from late spring to autumn is usually associated with a greying and finally a killing of the _Sphagnum_, noticeable from a distance even in the absence of the fruiting-bodies as paler patches in the rich green bog. Another agaric found only in _Sphagnum_ bogs is _Omphalina sphagnicola_ (Berkeley) Moser with decurrent gills and long, elongate, hyaline spores. At the margin of _Sphagnum_ bogs, the fungus _Mycena bulbosa_ can be found attached to the base of tufts of rushes. Potting up a sward of _Sphagnum_ and retaining it in a warm greenhouse during winter favours the bog agarics to fruit when other larger fungi are not available. ~Mycena bulbosa~ (Cejp) Kühner _Cap_: width 3-6 mm. _Stem_: width 1 mm; length 10-15 mm. _Description_: Cap: dirty white, greyish and very gelatinous. Stem: very thin, hyaline with a very distinct hairy, basal disc. Gills: crowded, adnexed, very short and whitish. Spore-print: white, but because it is so small it is often difficult to see.