166 



BASIDIOMTCETES 



and is the chief cause of a root-disease (red-rot) in Pines and Firs ; the fruit- 

 bodies develope a large number of basidiospores ; they may be very large and 

 are found just beneath the surface of the soil (on living or dead roots), and 

 exposed to the air (on felled stems and roots, in Scandinavia). 



Ptychogastcr has cushion-like fruit-bodies, which consist chiefly of chlamy- 

 dospore-chains, formed of ellipsoidal spores, which alternate with short hyphse 

 having transverse septa and clamp-connections. The hymenial portion is 

 limited to a small group of tubes. Ft. albus (Oligorus ustilaginoides) grows on 

 stumps of Conifers and forms irregular cushions, at first white and later on 

 brown, which consist almost entirely of chlamydospores. 



Boletus (Fig. 171) has a fleshy fruit-body resembling a common Mushroom, 

 with central stalk. The layer of tubes is easily detached from the pileus, and 

 the tubes are easily separable from one another. They grow on the ground in 

 woods. Edible species are: B. edulis, with thick, reticulate stalk; B. scaber, 



with thin stalk and rough pileus ; B. luteus, with 

 a ring on the stalk. B. luridus is poisonous, 

 its tubes have red openings, and the flesh turns 

 quickly blue when broken and exposed to the air. 

 Fistulina hepatica (Beef-steak Fungus), has a 

 red, fleshy, edible fruit-body, with red juice. 

 The tubes are individually distinct ; conidia are 

 also developed. Grows on old Oaks. 



Merulius lacrymans (" Dry-rot") has a resu- 

 pinate fruit-body with white, cotton-like border, 

 and the remaining portions covered by reticulate, 

 ramified veins of a rust-brown colour. In favour- 

 able vegetative conditions it is fleshy and exudes 

 large drops of water hence its specific name 

 and also the name " Tear Fungus." The my- 

 celium is at first colourless, and then yellow- 

 brown ; when dry it is tough and leathery. It 

 destroys the timber in damp houses, extends far 

 and wide over boards and beams and even over 

 the masonry, giving rise to a disagreeable smell 

 in the rooms in which it lodges. In woods the 

 Fungus lives on Pine-stems. It is brought from the forest on the logs of timber, 

 and is distributed from log to log by the mycelium and the basidiospores. 

 The living mycelium can be recognised by the clamp-connections shooting out 

 branches. The basidiospores are often ejected a distance of a metre ; they are 

 elliptical (10-11 /j. long and 5-6 fi broad), and germinate easily on damp wood, 

 or in fruit-juice which has been neutralized with urine or alkaline carbonates. 



Dtfdalea (Labyrinth Fungus), has bracket-like, corky fruit-bodies with irregu- 

 larly-folded plates or discs on the under side. It forms a transition to the 

 Agaricaces. D. quercina is frequent on Oak- stumps. 



Order 6. Agaricacese (Mushrooms, Toadstools). The 



hymenophore consists of knife-like plates (lamellae, gills), which are 

 situated on the under side of the umbrella-like pileus of the frnit- 



<i 



FIG. 171. Boletus edulis (about 

 Jth) : b, longitudinal section of 

 a portion of the pileus. 



