CURREY, ON FUNGI. 123 



This membrane is not visible unless the edge of the spore be 

 exactly in focus. Mr. Busk, without my having called his at- 

 tention to it, noticed the existence of this membrane in some 

 spores of the Uredo of Pucchiia pidverulenta which I sent to 

 him, and thought that he could perceive a slight blue tinge 

 in it upon the application of iodine and sulphiuic acid. 



Xeaodochuscm'bonarius, Schlecht. — This plant, first observed 

 by Schlechtendal, and described by him in the ' Linnsea/ 

 vol. i, p. 237, pi. iii, is mentioned in the 'Annals of Natural 

 History' to have been found by Mr. Churchill Babington, in 

 Leicestershire, and I have received specimens of it from the 

 Rev. A. Bloxam, but it seems to be of rather uncommon occur- 

 rence. It has been found only on the leaves of Sanguisorba 

 officinalis, and was formerly supposed to be parasitical upon 

 Uredo miniata, in company with which it grows. There can 

 be little doubt that the Uredo, like those of Phragmidium, 

 Puccinia, &c., is the produce of the same Mycelium as the 

 Xenodochus itself. The fruit forms little black tufts, which 

 differ in no respect to the naked eye from the tufts of 

 Phragmidium. One of these fruits, in its natural state, is 

 represented in fig. 34, magnified 220 diameters. If treated 

 in the manner mentioned above, with regard to Phragmidium, 

 it will be found that their structure differs in no respect from 

 those of the latter plant. It will be seen that each consists 

 of a clear outer membrane, enclosing a multitude of ringed 

 cells, each of which latter cells has another cell in its interior, 

 which under the action of the acid is set free, and exhibits a 

 well-defined, circular nucleus. There is, in fact, no difference 

 between Phragmidium and Xenodochus, excepting the num- 

 ber of the ringed cells of the latter, unless there be a difference 

 in the number of the pores, which, however, would be a very 

 unsatisfactory ground of generic distinction. In fig. 34 is 

 seen a bead-like row of cells proceeding from one of the 

 upper joints of the Xenodochus, and which appeared after 

 the fruit had been kept in water for some hours. I do not 

 suppose this to be the normal mode of germination of Xeno- 

 dochus, for it is hardly likely that its germination should 

 differ materially from that of Phragmidium, Puccinia, and Tri- 

 phragmium. Small cells of the nature of those forming 

 the beads in fig. 34 are sometimes given out by the spores of 

 fungi, and the process is perhaps analogous to that which 

 takes place in some of the lower fresh-water Algse. In some 

 spores of Spirogyra, for instance, which I gathered in the 

 month of March last year (1856), and kept by me to watch 

 their germination, although many of them, when the proper 

 time arrived, became green and threw out their regular 

 germs, there were many in which the contents became trans- 



