P YRENOMYCETES. 



289 



Eurotium and Penicillium. In another species, Peziza 

 fusarioides, the conidial stage has been pretty cftjtainly de- 

 termined to be the growth which was formerly supposed to 

 be a species of Dacrymyces ; it consists of little tubercles 

 which contain slender linear bodies on branched threads. 

 Bulgaria sarcoides is known to bear coiiidia in an earlier 

 stage, which was formerly referred to the genus Tremella 

 (Hymenomycetes) . * 



(a) The principal genus of this order is Pesfal, which contains many- 

 species ; they are common on the ground in forests. Ascdbolus furfu- 

 raceus is common on cow dung. Morchella esculeuta, the Morel, grows 

 on the ground in forests. It attains a height of from 10 to 15 centim- 

 etres (4 to 6 inches), and bears its hymenium in shallow depressions 

 of its convex surface. 



(6) The Morel is edible, and is much used for food in some places. 

 According to Dr. M. A. Curtis, some species of Helvetia, also, are edible. 



(c) Peziza syhatica, P. Candida, and Cenangium Piri occur as fossils 

 in the Tertiary. 



382. Order Pyrenomycetes. The plants of this order 

 are parasitic or saprophytic in habit ; their tissues are usually 

 hard and somewhat coriaceous, differing in this respect from 

 the Helvellacece, which are generally fleshy ; they differ also 

 from the plants of the last-named order in having the hyme- 

 nium imbedded in deep cavities (perithecia) with narrow 

 openings. In other respects the Pyrenomycetes present a 

 close similarity to the ffelvellacece, to which they are doubt- 

 less closely related. 



383. Their general structure may be illustrated by a 

 couple of examples. In Claviers purpurea, the fungus 

 which produces ergot on rye and other grasses, the first 

 stage consists of a profuse growth of the mycelium in the 

 tissues and upon the surface of the young ovary (s, A, and 

 B, Fig. 198). In this stage, which is called the Sphacelia 

 stage, it produces a multitude of conidia on the ends of 

 hyphse which grow out at right angles to the surface of the 

 mycelial mass (C, Fig. 198, b and p) ; these conidia fall off 

 very easily, and quickly germinate (D, Fig. 198), giving 

 rise under favorable circumstances to new sphacelia, which 

 in turn may produce conidia, and these, new sphacelia, and 



* See further, De Bary, op. cit., p. 200. 



