SPORES AND SPORIDIA. 85 



above indicated, and it would be a manifest advantage if mycolo- 

 gists generally would adopt this distinction, which they would find 

 of great practical use to themselves. Lichenologists would per- 

 haps follow the example, but we fail to recognize any reason for a 

 compulsory act of uniformity. 



It is a matter of secondary importance whether " thecaspo re" 

 or " sporidia " be the accepted term, provided "thecaspore" be 

 employed as a mycologist or lichenologist would employ it, and 

 not as synonymous with the spores developed in the theca, or 

 capsule, of mosses. It is so easy when the same term is applied to 

 two different things for wrong impressions to gain ground, hence 

 we find some persons jumping to the conclusion that because theca 

 has been applied to the capsule of mosses, it is equivalent to tlieca 

 when applied to the ascus of a fungus or lichen, and therefore that 

 thecasjiores, whether of fungi or of mosses, are the same. This is 

 a manifest eiTor, as there is probably much closer resemblance 

 between the peridia and spores of a Craterium and the capsule and 

 spores of a moss than in any other genus of fungi, and in Craterium 

 there are no asci and sporidia. 



It needs very little argument to show that in dealing with some 

 thousands of species of plants in which there is, within certain 

 limits, great variability in the repi'oductive organs, it is a manifest 

 advantage to possess well defined terms, and if there is any 

 permanent feature which would enable the botanist to divide the 

 whole into two sections, applying a definite term to each, labour 

 and confusion would be diminished. It is contended that probably 

 half the species of fungi have spores generated in membranous sacs, 

 which the mycologist calls asci, and the lichenologist thecce. The 

 spores so produced are designated sporidia. The remaining half 

 the number of species have naked or free spores, i.e., spores not 

 generated in asci — to these it has been suggested that the term 

 spore should be limited. Speaking or writing of sporidia, so 

 characterized, a definite idea is at once conveyed of reproductive 

 bodies, produced within an ascus, as opposed to the naked spores, 

 which a more restricted use of the term " spore" would convey. 



The term " sporidia " has been, and is still employed by Con- 

 tinental mycologists, but unfortunately without any definite idea 

 being associated with it, so that it has almost the same signification 

 as the term "■ spore" in its widest sense. Fuckel, it is true, uses 

 sporidia in all his Ascomycetes, but whilst employing spores in 

 Agaricus, he reverts to sporidia in Boletus. The antithesis to 

 sporidia recognized by this author appears to be stylospores. There 

 is certainly a want of uniformity amongst mycologists on this 

 point, but this may proceed rather from ignorance of the meaning 

 attached to the word, when it was first proposed, than from a rejec- 

 tion of the principle involved. 



If the term " sporidia " were universally adopted for thecaspores, 

 or spores contained in asci, the residue of spores to be dealt with 



