260 MR. F. CURREY ON THE FRUCTIFICATION OF COMPOUND SPHiERI^E. 



Micrometric measurements of length should always be given. The size of sporidia is 

 of course subject to variations dependent upon the circumstances of growth of the plant 

 producing them, but as a general rule these variations take place within narrow limits. It 

 not unfrequently happens that the sporidia increase iri size after their escape from the 

 ascus, so that measurements taken from specimens in which the asci have disappeared, 

 wiU often be found to exceed the mean lengths of the sporidia when measured in the 

 interior of the ascus. 



I will conclude these introductory observations with a caution, superfluous to practised 

 microscopists, but which may not be without its use to others who may consult the 

 measurements here given ; viz., that it is indispensable for correctness of observation to 

 ascertain with accuracy the magnifying power of their object-glasses. Opticians, as is 

 well known, always fm'nish tables giving estimates of the magnifying powers, but the 

 tables are not (nor do the opticians profess that they are) minutely accurate. They ex- 

 press, in fact, the magnifying power aimed at, not that actually attained ; and it will be 

 found in practice that in object-glasses of the same focal length, no two wiU magnify 

 exactly the same number of diameters. In the measurement of objects so minute as the 

 sporidia of many of the Sphcerice, great accuracy is indispensable for avoiding erroneous 

 conclusions. I need hardly add that the correct determination of the value of the micro- 

 meter divisions is equally necessary. The arrangement of the " Sphserice compositse" 

 according to the * Systema Mycologicum' is subjoined, with the essential characters of the 

 genus, sections and divisions. 



SPHiEEIA, HaU. 



Char. — Perithecia rounded, entire, perforated at the apex. Asci mixed with paraphyses, convergent, 

 deliquescent. Sporidia various. 



A. COMPOSITE. 



Section I. Periphericj!. — Perithecia more or less divergent, situated in the periphery of the 

 stroma; ostiola even, destitute of a neck. 



Div. 1. CoRDYCEPS. — Stroma club-shaped, erect, simple or branched, stipitate. 



Div. 2. PoRONiA. — Stroma marginate, cupshaped, open. Perithecia ovate, situated in the disk of 



the cup only, destitute of a neck ; ostiola even and prominent. 

 Div. 3. Pulvinat^. — Stroma sessile, convex, more or less hemispherical, immarginate. Perithecia 



in the periphery of the stroma. 

 Div. 4. Connat/e. — Stroma widely effused, indeterminate, immarginate, plane, surrounding the 

 perithecia, or arising from their confluence. Perithecia destitute of a neck, immersed in the 

 stroma, or protruding. 

 Section II. Hypopheric^. — Perithecia vertical, immersed, covered with the stroma, and having an 

 attenuated neck. 



Div. 5. Glebos^. — Stroma more or less effused, determinate, glebose, distinct from the matrix, 

 at length rigid and brittle. Perithecia ovate, large, at first buried and mouthless, at length 

 attenuated into a short neck; ostiola even. 

 Div. 6. LiGNOSiE. — Stroma effused, thin, plane, more or less determinate, connate with the matrix; 

 circumscribed with a black line. Perithecia sunk down to the bottom of the stroma, crowded, 

 with prominent ostiola. 

 Div. 7. Versatiles. — Stroma immersed, at length emergent, determinate, but confluent with the 



