160 



BOTANY. 



little potaasic hydrate. Look for conidia and suckers (haustoria) 

 Look also for spore-fruits, wliich 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. 



(J) Collect and study the blights to be found on hops (Sphaerotheca 

 castagnei), on cherry- and apple-leaves (Podosphaera tridactyla), on 

 hazel- and ironwood-leaves (Phyllactinia suffulta), on willow-leaves 

 (Uncinula adunca), on leaves and fruit of grapes (U. amerioana), 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 (3d) covered with minute yellow globular 

 bodies (the spore-fruits). These are known as 

 the Herbarium-mould (Eurotium herbariorum). 

 Study as in case of the blights. ' 



333. The Truffles {Order Tuberacem) 

 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- 



Fio. 84.— .4, a small 



slice of the spore^Stt cillium) are members of this order, and 



of a truffle (iSiber me- 

 lanosporum), showing 

 sacs and spores; B^ a 

 sac and its spores, more 

 enlarged. 



are in reality minute truflB.es. The coni- 

 dial stage is the common Blue Mould on 

 decaying fruit and pastry (Fig. 85). The 

 sexual organs resemble those of the herbarium-mould, and 

 the spore-fruit is a minute truflie-like body as large as a 

 coarse sand-grain. 



Practical Studies. — (a) TruflSes are natives of Europe, but they may 

 be obtained for study in our markets. 



