l66 ROCHESTER ACADEMY OF SCIENCE. 



but the following-, which the author travelled, has been ever full of 

 opening vistas, pleasant surprises and happy work. He started on 

 his mycological trip in the autumn, among the mildews. In autumn 

 we often find the leaves of living plants overrun by the white mycelium 

 of mildew. If we examine a leaf thus infected, closely and with a lens, 

 we may find, scattered among the mycelial fibres or on the surface of 

 the leaf, minute black dots like grains of black pepper. If we wet 

 such a surface with dilute alcohol, to free from air bubbles, and trans- 

 fer one or two of these black specks and a bit of the accompanying 

 mycelium to a drop of water on a slide; and cover with a cover glass, 

 then examine under a microscope, we shall see a globe-like body 

 surrounded by appendages. This fruiting globe-like body is called 

 the perithecium. If with gentle pressure upon the cover glass we 

 crush a perithecium we may see it burst asunder and some oval sac- 

 like bodies, called asci, escaping from the rent. Within these sacs we 

 may also see some rounded forms which are the spores, — ascospores 

 they are called from being contained in asci. They are also termed 

 sporidia. As we continue our study of other forms of mildew we shall 

 find variations in mycelium, perithecia and appendages, asci and 

 sporidia. After we have studied the various forms of parasitic 

 pyrenomycetes during the fall and winter months we shall be in a 

 position to consider the saprophytic members upon wood, bark, dead 

 stems, and decaying vegetation, the following March and April, 

 months especially favorable for their collection. We shall find that 

 the saprophytic pyrenomycetes also have perithecia, asci, and sporidia, 

 diflering in structure from the forms we observed in the mildews, and 

 from other saprophytic forms. While some are superficial, many are 

 immersed in bark or wood, or in a special matrix, called the stroma, 

 from which they may erupt. Thus little by little we shall advance in 

 our knowledge. The following represent the morphological features 

 whose variation and resemblances we seek to study in descriptive 

 pyrenomycetology : 



1. Mycelium and subiculum. 



2. Stroma. 



3. Perithecium. 



4. Asci. 



5. Paraphyses. 



6. Sporidia> 



