170 OBSERVATIONS ON PEZIZA CALYCINA. 



Tis that some species o? Peztza are mucli more variable than others, 

 such for instance as Peziza scutellata and Peziza calycina. This, 

 however, should cause us hesitation in constructing or accepting 

 new sf)ecies based on such variability. 



Dr. Rehm proposes Peziza laricis, on what we consider an un- 

 tenable basis, for reasons which we will presently detail. The 

 grounds on which Dr. Rehm's proposition rests, are apparently 

 three, viz. : — 



1. Size and form of sporidia. 



2. Texture of the asci. 



3. Reaction with tincture of iodine. 



F'i7'st. — As to the size and form of the sporidia. However much 

 a difference in size and form of sporidia may be valued in the de- 

 termination of the limits of species, it is clear that these differences 

 must be constant, and confined to the forms separated. In the 

 two species indicated by our correspondent he describes the spori- 

 dia thus — 



P. cahicina. Sporidia elliptic, -OIS-OIS X '005 m.m. 



P. laricis. Sporidia obtuse-elliptic, •016--018 X •006--007 m.m. 



The differences, therefore, are simply that the sporidia in P. 

 laricis are more obtuse, and broader than in P. calycina. If we 

 accept the types of the two species which he gives, these will lead 

 us to estimate the value of this distinction. These are — 



P. calycina. Fungi Britt. i., 474, ii., 369, A. b. 



P. laricis. Fckl. F. Rhen., 1206. Rehm Asc, 62. Thumen 

 H, CE. Myc, 191, Fungi Britt., ii., 370. 



Attention must now be directed to our plate 66, containing 

 figures of sporidia derived from these published specimens. 

 Fig. a, is from Fungi Britt., i., 474. 

 ,, d, is from Fungi Britt., ii., 369 a. 

 „ e, is from Fungi Britt., ii., 369 b. 

 all of these are referred to P. calycina. 



Fig. h, is from Fungi Britt., ii., 370. 



We have no copy of Thumen's " Herb. Myc. GEcon.," hence 

 have been unable to figure the sporidia in his No. 191. 



In our specimens of Rehm's " Ascomyceten," the sporidia un- 

 fortunately are mostly granular, and unformed in the asci, being 

 immature, so that we could obtain no figures of the mature spo- 

 ridia, which aj)peared to be similar to those figured at b. 



These figures are drawn by camera lucida from the sporidia, and 

 represent, in all cases, such free sporidia as presented themselves 

 at the same time on the field of the microscope. These drawings 

 have been reproduced by photo-lithography, on the plate, so that 

 it may fairly be presumed that they are accurate delineations of 

 the objects themselves. 



From these figures it is evident that, as to width of the sporidia, 

 there is no distinctive feature of difference between fig. h and the 



