80 Proceedings 
the head of conidia, the projections shrivel up and the main 
hypha pushes on to form a further similar head at a short 
distance from the first; it may also send out side branches 
which bear successive fertile heads. This then is the sum- 
mer or conidial stage and represents the Botrytis fungus. 
In some forms of Botrytis there seems to be no other 
stage, but in the case of the lily disease another form has 
been discovered. At some stage of growth, the mycelium 
develops a close ball of thread, so compact and so tightly 
interwoven that,when it is cut through, it seems exactly likea 
continuous tissue. These bodies are about the size of a 
small pea, quite black on the surface and white inside, and 
called, from their hard nature, Sc/evotia, from a Greek word 
signifying hard. These hard little bodies represent the 
resting stage of the fungus and they retain their vitality a 
fairly long time, in any case they last through the winter. 
In spring,when the moist warm weather comes, they wake 
up and begin to grow out: it may be into a tangle of myce- 
lium only,or a growth of Botrytis conidiophores, or there may 
be formed a stout elongated stalk ending in a cup shaped 
Peziza fungus, called Sclerotinia, the inside of the cup—the 
disc—being lined with closely packed stout tubes each con- 
taining eight spores. When these spores alight on a favor- 
able soil they germinate exactly like the conidia; they form 
mycelium and sometimes go on to produce conidiophores 
and Botrytis heads of conidia. The complete life-cycle is 
not reproduced in all the species; there may be the Botrytis 
form only, the conidia or mycelium of which manages to 
persist during the winter, ready to become active again in 
the warmer weather. Very frequently the variation lies 
between the loose mycelium and the hard Sc/erotza; this is 
the case in the clover disease, the mycelium burrows in 
the plant and balls itself up into Sclerotia. Neither Botrytis 
nor Sclerotinia has ever been detected in this species; when 
the Sclerotium germinates it produces mycelium only. 
Again there is a Sc/erotium that is frequently to be found 
in autumn on stems of dead herbaceous plants such as the 
larger Umbelliferz : in cultivation it always produces dir- 
ectly a fluffy growth of Botrytis. These fungi seem to vary 
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; . 
; 
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ae es ia RREN Ss sec aene or 
Bese es os res 
