160 BOTANY. 
little potassic hydrate. Look for conidia and suckers (haustoria) 
Look also for spore-fruits, which appear like minute dark dots to the 
naked eye. Carefully crush the spore-fruits and observe the sacs 
(4 to 7) with their contained spores (6). Notice the beautifully 
branched tips of the appendages. 
(6) Collect and study the blights to be found on hops (Spheerotheca 
castagnei), on cherry- and apple-leaves (Podosphera tridactyla), on 
hazel- and ironwood-leaves (Phyllactinia suffulta), on willow-leaves 
(Uncinula adunca), on leaves and fruit of grapes (U. americana),'on 
wild sunflowers, verbenas, etc. (Erysiphe lamprocarpa), on peas (E. 
martii), on grass, anemones, buttercups, etc. (E. communis). 
(c) Place a few slips of green twigs in an 
ordinary plant-press, allowing them to remain 
until they become (1st) mouldy (conidial state), 
and (2d) covered with minute yellow globular 
hodies (the spore-fruits). These are known as 
the Herbarium-mould (Eurotium herbariorum). 
Study as in case of the blights. 
ioe 
333. The Truffles (Order Tuberacec) 
are well known from their large under- 
ground spore-fruits, which are edible. 
Internally there are narrow tortuous 
channels on whose walls sacs develop, 
each containing a number of spores (Fig. 
84). Little is known of their round of 
life, and the sexual organs have not been 
discovered, 
334. The Blue Moulds (species of Peni- 
ee ho ae Small cillium) are members of this order, and 
fanocnortm, ‘showing are in reality minute truffles. The coni- 
ee now dial stage is the common Blue Mould on 
iene decaying fruit and pastry (Fig. 85). The 
sexual organs resemble those of the herbarium-mould, and 
the spore-fruit is a minute truffle-like body as large as a 
coarse sand-grain., 
Practical Studies.—(a) Truffles are natives of Europe, but they may 
be obtained for study in our markets, 
