132 DIMORPHISM IN FUNGI. 



abundance of the mould. The perfect form, SphcBvotheca pan7iosa, 

 has a very small conceptacle, containing only one spore-case, and 

 is surrounded by simple threads. 



Two very destructive mildews — viz., that attacking the vine 

 and that attacking the hop — also belong to this group. In the 

 case of the vine disease, the conidial form alone is known, under 

 the name of Oidium Tiickeri. The Erysiphe form has not yet 

 been found. In the case of the hop disease, the perfect form is 

 SphcerotJicca Castagnei. The conceptacle here is small, and 

 contains only one sporangium, or spore-case, and is furnished with 

 only simple appendages. It will be remembered that in my 

 various papers on " Saprolegnia,"* " Peronospora,"t and " Cysto- 

 pus,"J I described in each case a conidial form and a perfect form 

 or oospore. 



Another interesting example is to be found in Hypomyces, a 



genus of the order Sphmiacei, generally parasitic on the larger 



fungi. The Hypoinyces^ in its conidial stages, first attacks the 



host-fungus— say, a Boletus. Its mycelium runs through the 



Boletus^ reducing the whole fungus to a mass of golden powder, 



which falls to pieces on the gentlest touch, thus preparing the 



pabulum necessary for the nourishment and perfection of the 



higher ascigerous form, which is found in a stroma developed in 



the ground. This generally consists of a bright-coloured perithe- 



cium, enclosing numerous octosporous asci of an elongated form. 



The conidia — or, as they are sometimes called, micro-conidia — 



have often been described as autonomous species of Mticedmes, 



such as Botrytis, Daciyltum, etc. Besides the micro-conidia, a 



further form of fructification is sometimes found called macro- 



conidia, which are large spores, having a thick echinulate coat, of a 



bright colour. These have also been reckoned as separate species, 



especially under the name of Lepidotmoii, allied to the Mticedines. 



Another well-known example is that of Tubcrcularia vulgaris 



and Ncdria Cinnabarina, described formerly as separate fungi, 



but now known to be the same, Tuberada^-ia being the conidial 



form, Nectria the perfect ascigerous form. The two forms may be 



* Sec this Journal, Vol. II., p. 1S5. 



t „ „ Vol. III., p. 1S6, 197. 



% „ „ Vol. IV., p. 135. 



