294 BOTANY. 



bodies pycnidio-spores. Neither the spermatia nor the 

 pycnidio-spores have been known to germinate ; but from 

 the resemblance of the former to those of Oucurbitaria, 

 Valsa, and other genera of this order, which have been seen 

 to germinate,* it is quite certain that they, at least, are 

 reproductive, and that "they are the agents for the dissem- 

 ination of the species to a great distance," for which they are 

 fitted by their extreme minuteness. In all probability the 

 pycnidio-spores have also a similar function. 



389. Xo sexual organs have as yet been observed. 

 Doubtless they exist in the dense tissues of the knot, and 

 fertilization probably occurs in the spring or early summer, 

 while the conidia are being produced on the surface of the 

 young knot. 



39O. The hyphae of each year's knot generally penetrate 

 downward some centimetres into the uninjured bark, and 

 remain dormant there until the following spring, when they 

 begin the growth which results in the production of a knot, 

 as described in paragraph 386. 



(a) The Pyrenomycetes include a large number of exceedingly in- 

 jurious fungi ; they often attack and destroy not only plants, but also 

 insects, upon which their ravages are in many cases very great. 



(&) The classification is as yet in gr;'at confusion.f The principal 

 genus is Sphm ia, which contains many species. Valsa, Diutrype , and 

 Hypoxylon are other important genera. 



(c) Good specimens of Claviceps purpurea may be obtained from 

 almost any rye-field, and more certainly from the isolated hunches of 

 rye growing here and there in many fields. By making repeated ex- 

 aminations soon after the flowering of the rye the conidia may be 

 obtained ; and by gathering the sclerotia and burying them in moist 

 sand under a bell-jar, the receptacles may be grown. 



(d) Specimens of Spfuzria morbosa for study should be gathered at 

 different times in the season from early spring to the latter part of 

 the winter following. The first gathered will be necessary to the 



* Dr. Max Oornn, in " Annales des Sciences Xaturelles," Sixtli Series, 

 Vol. III., gives the details of his experiments upon germinating the 

 apermatia of many Pyrenomycetes. A translation appeared in " Gre- 

 villea," 1877 and 1878, Nos. 36 to 39. 



f The student may profitably consult, in studying this difficult order, 

 the finely prepared sets of " North American Fungi," by J. B. Ellis, 

 begun in 1878, and still continuing. 



