FLOWERLESS PLANTS 461 



make a single puncture with a pin in the second and 

 rub in some mould spores or a little dust ; put this away 

 with the first ; and let them puncture the third, but, 

 instead of inoculating it, let them leave it, puncture side 

 up, exposed to the air on their desks. They may vary the 

 experiment still further by having different pupils use for 

 their inoculations a number of the moulds described 

 below. This experiment coordinates itself with practical 

 fruit culture and the need of " hand picking " of choice 

 fruit. It also carries a larger lesson related to intelligent 

 cleanliness in care of the skin and treatment of scratches, 

 cuts, and bruises, since in this function of protection the 

 skin of an apple and that of a child are much alike. 



Our experiments and observations cannot go far before 

 we see that there are many different kinds of moulds. 

 We notice, first, that while the mycelia of all appear much 

 alike to the naked eye (generally white, like cotton bat- 

 ting), the spores are of different colors ; and these may 

 serve as a basis for elementary classification. 



Blue Mould, Penicilliumglaucum* This is the commonest mould 

 we have, and its blue velvety growths over bread and all sorts of foods 

 and on the leather of shoes and gloves have made it only too familiar 

 to all. Its manner of spore formation is shown in Fig. 190, b. 



Black Mould, Aspergillus niger. This is another common house- 

 hold form on bread, vegetables, and fruits. 



White Mould, Mucor mttcedo. The white moulds are especially 

 good for elementary lessons on account of their comparatively large 

 size. They grow on all kinds of food, and after covering the mass 

 with a white cottony mycelium they send up fruiting hyphae, often 

 one or two inches in height, which terminate in little black beads 

 miniature puffballs in which the spores are produced. These 

 are seen, enlarged in Fig. 190,^, and natural size in the "mould 

 gardens" in Fig. 189. 



