KITCHEN-GARDEN VEGETABLES. 
Mushroom (Agaricus campestris) (fig. 1220). | above-ground occurs chiefly in the night. 
—The Common or Field Mushroom grows wild 
in meadows, pastures, &c., and is most abundant 
in autumn. It is also largely cultivated, and 
in some countries Mushroom production has 
developed into quite an important industry. 
Like all Fungi it produces spores in abundance, 
but these in the field Mushroom do not appear 
to vegetate. It is, however, easily multiphed 
by means of the mycelium or ‘“‘spawn”. This 
has the appearance of a white thread-like mould, 
which retains its vegetative powers for many 
years, provided it is kept dry; but if placed in 
a proper medium, and afforded heat and mois- 
ture, 1t ramifies in all directions amongst the 
soil or other substances favourable to its growth. 
When the spawn begins to run, as it is termed, 
it may be propagated to a great extent. The 
spawn may be safely exposed to a temperature | 
of 80°. Proof of this is afforded by the fact that, 
if inserted in Melon-beds, it increases or runs 
in the soil, whilst the Melons are growing in 
a temperature of 80°; and when the crop of 
Melons is ripened off, the beds cleared and suffi- 
ciently watered, and the temperature lowered, 
a crop of Mushrooms springs up. 
Light is not essential for the growth of Mush- 
rooms, for, although they grow naturally in open 
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Fig. 1219.—Morel (Morchella esculenta). Mature and young specimens. 
pastures, and dislike moist shady situations in 
which many other species of Fungi abound, 
yet it will have been observed that in those 
pastures the development of the Mushroom 
| 
463 
The 
Mushroom is of course exposed to light during 
the day, and that may be of importance in per- 
lia’, 
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Vig. 1220.—Mushrooms (Agaricus campestris) 
fecting the spores; but in other respects light 
is not essential. The Mushroom makes in the 
open pasture the bulk of its substance in the 
night, and even the salmon-coloured tinge of 
the gills is acquired in the dark. 
Mushrooms, like other species of Fungi, 
abound in nitrogen; this substance must there- 
fore be considered a necessary element of their 
nutrition, and unless substances rich in nitrogen 
are supplied, their cultivation cannot be attended 
with success. Nitrogen is found in considerable 
quantity in the dung of horses and cows, and 
accordingly these substances are generally em- 
ployed in the cultivation of the Mushroom. 
They are subjected to fermentation, but this 
evidently must not be carried too far, otherwise 
the nitrogen would be driven off in the form of 
ammonia. The substances from which the 
Mushrooms derive their principal supply of 
nourishment require to be coated with some 
earthy material, so as to absorb the ammonia 
which would be driven off by fermentation; 
they must also be rendered compact by tread- 
ing or beating, in order that the fermentation 
may be rendered slower, and consequently more 
lasting. 
Preparation of the Spawn.—For the artificial 
production of Mushrooms, good spawn is neces- 
sary. Brick spawn (fig. 1221), so called from the 
materials being worked up ana cut or moulded 
like bricks, is made as follows: Fresh horse-drop- 
pings, cow-dung, and a little loam are mixed 
