for the Microscope. 47 



bicotor}. The most common of all the black masses of 

 spores which issue from the bark of fallen twigs is one 

 with simple ovate spores, each containing a large nucleus. 

 It is most common on birch. 



333. CORNEL STILBOSPORE (Stilbospora angustata}. 

 This is another of the species in which the spores issue 

 in a black mass. It is found on twigs of cornel, and has 

 fine brown spores, divided by three septa, which resemble 

 the spores of some of the Spheriae. (PI. V., fig. 22.) 



334. BIRCH PROSTHEMIUM (Prosthemium betulinuni). 

 Dead birch twigs foster another parasite, with large 

 septate spores ; but in this instance two or three are 

 clustered together in a bundle, and attached to colourless 

 threads, which have the appearance of rootlets. The 

 majority of this kind of fungi, on dead sticks, are to be 

 sought in early spring. (PI. V., fig. 38.) 



335. ALDER PROSTHEMIUM (Prosthemium stdlare). 

 On dead alder sticks, but not common. The spores are 

 septate, and clustered in a radiating star-like manner at 

 the apex of a common stem. In both instances the 

 spores are produced within a special receptacle (perithe- 

 cium), more or less imbedded in the bark. (PI. V., fig. 21.) 



336. NETTLE FLASKS (Apospharia acuta). Old nettle 

 stems will in the spring exhibit a number of black flask- 

 shaped bodies clustered about the lower portion of the 

 stem. These flasks are ' perithecia,' and in their interior 

 are very minute free sporidia, or larger and true spores 

 contained in long membranous ascL In the latter case 

 the fungus is a true Sphnsria, in the Tormer only a con- 

 dition or phase of the Sphasria, which continues to bear 

 a separate name, as here applied to it. 



337. COMMON DIPLODIA (Diplodia vulgaris}. This 

 represents a large number of species growing on dead 

 twigs or dead leaves. The perithecia contain a number 

 of free spores, which are at first colourless and undivided, 

 but at length are divided across the centre, and in many 

 instances acquire a brown colour. When mature, they 

 escape thrqugh an orifice at the apex of the perithecium. 

 (PI. V, fig. 34.) 



