POLYMORPHISM. 197 



from the foregoing, finds illustration in the spharriaceous genus 

 Melanconis, of Tulasne, in which the free spores are still called 

 conidia, though in most instances produced in a sort of spurious 

 conceptaculum, or borne on short threads from a kind of 

 cushion-shaped stroma?. In the Melanconis stilbostoma,* there 

 are three forms, one of slender minute bodies, oozing out in the 

 form of yellow tendrils, which may be spermatia, formerly called 

 Nemaspora crooea. Then there are the oval brown or olive brown 

 conidia, which are at first covered, then oozing out in a black 

 pasty mass, formerly Melanconium bicolor, and finally the sporidia 

 in asci of Sphceria stilbostoma, Fries. In Melanconis Berkeleii, 

 Tul., the conidia are quadrilocular, previously known as Stilbo- 

 spora macrosperma, B. and Br. In a closely-allied species from 

 North America, Melanconis bicornis, Cooke, the appendiculate 

 sporidia are similar, and tho conidia would also appear to partake 

 of the character of Stilbospora. We may remark here that we 

 have seen a brown mould, probably an undescribed species of 

 Dematiei, growing in definite patches around the openings in 

 birch bark caused by the erumpent ostiola of the perithecia of 

 Melanconis stilbostoma, from the United States. 



In Melanconis lanciformis,\ Tul., there are, it would appear, 

 four forms of fruit. One of these consists of conidia, charac- 

 terized by Corda as Ooryneum disciforme.% Stylospores, which 

 are also figured by Gorda under tho name of Coniothecium betu- 

 linurn ; pycnidia,§ first discovered by Berkeley and Broome, and 

 named by them Hendersonia polycystis ; || and the ascophorous 

 fruits which constituted the Sphceria lanciformis of Fries. Mr. 

 Gurrey indicated Hendersonia polycystis, B. and Br., as a form 

 of fruit of this species in a communication to the Royal Society 

 in 185 7. If He says this plant grows upon birch, aud is in per- 

 fection in very moist weather, when it may be recognized by the 



•Cooke, " Handbook," ii. p. 878; Tulasne, " Carpologia," ii. p. 120,, 

 plate H. 



f Tulasne, "Selesta Fang. Carp.," ii. plate 16. 



J Corda, " Icones Fungorum," vol. iii. fig. 91. 



§ Corda, "Icones," vol. i. fig. 25. 



|| Berk, and Br. "Ann. Nat. Hist." No. 415. 



t Cuvrey, in " Philosoph. Trans. Eoy. Soc." (1857), pi. 25. 



