ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1001 



Double Lichen.* — Herr W. Zopf has observed upon Physma compactutn 

 and on other Collemacei, reddish-brown warty protuberances, which were 

 found to be the imbedded flask-shaped perithecia of an Ascomycete, 

 Pleospora Gollcmatum n. sp. This fungus is not parasitic upon the lichen, 

 but is in direct connection with the constituent alga, a species of Nostoc ; 

 and we have here a lichen made up by the symbiosis of two fungi with one 

 alga. The mycelium of the Pleospora, easily distinguished by its yellow 

 colour, penetrates the lichen to the base of the perithecia. When ready for 

 fructification the perithecia emerge on the surface of the lichen in the form 

 of reddish-brown protuberances ; the thallus of the lichen surrounds the 

 perithecia like a wall. 



Microchemical reactions of Lichens-I — According to Dr. E. Bachmann, 

 the chemical reaction characteristic of certain species of lichen, the appear- 

 ance of a yellow colour, afterwards turning to red, when a drop of potash- 

 ley is placed on the thallus, depends on the formation of very minute 

 needle-like crystals, of a rusty or blood-red colour, collected in groups or 

 in a dense felt. These are insoluble in glacial acetic acid, but are dissolved 

 by concentrated hydrochloric acid with a yellow colour. This reaction 

 occurs in Urceolaria ocellata, Pertusaria Isevigata, Lecidea lactea, L. Pilati, 

 Lecanora subfusca f. chlarona, Asjncilia aclimans f. glacialis, A. alpina, A. 

 cinerea, and Parmelia acetabulum. The yellow colour appears at once, the 

 separation of crystals after a few minutes. 



Hesse obtained from Cahjcium clirysocephalum a yellow crystallizable 

 pigment, insoluble in and unchanged by potash-ley, to which he gave the 

 name calycin. The same reaction is exhibited by Physcia mediana, Cande- 

 laria vitelUna, C. concolor, and Gyalolechia aurella. Other microchemical 

 tests are given, by which particular species of lichen can be distinguished 

 from their nearest allies. 



Emodin in Nephroma lusitanica.} — In the medullary tissue of this 

 lichen, Herr E. Bachmann finds a pigment closely allied in its products 

 to chrysophanic acid, but still dilfering from it. It appears to be identical 

 with emodin, known at present in the root of the rhubarb, and in the bark 

 and berries of Bhamnus Frangula. 



Introduction to the Study of Lichens.§ — Mr. H. Willey's work under 

 this title is a revised edition of his 'List of North American Lichens,' 

 published in 1873, with an enumeration of all species discovered since that 

 date, and descriptions of eleven new species. It contains also a condensed 

 account of the main facts concerning the structure of Lichens and their 

 classification. The plates represent the spores of North American genera. 



Fungi. 



Action of Pyrofuscin on Fungi. || — Herr P. F. Eeinsch finds that a 

 solution of pyrofuscin acts rapidly and destructively on living mould-fungi 

 such as Aspergillus. He suggests that this discovery may have an important 

 bearing in medicine, in the treatment of diseases due to parasitic fungi, 

 such as croup ; pyrofuscin being entirely without any injurious influence 

 on living human tissues. 



* Verb. KK. Zool.-Bot. Gesell. Wien, 1887 (1 pi.). 



t Flora, Ixx. (1887) pp. 291-4. 



X Ber. Deutsch. Bot. Gesell, v. (1887) pp. 192-4. 



§ Willey, H., ' An Introduction to the Study of Lichens,' 43 pp., Suppl. and 10 pis. 

 New Bedford, U.S.A., 1887. See Prof. W. G. Farlow in Amer. Journ. Sci., xxxiv. 

 (1887) p. 75. 



II Deutsch. Chem. Ztg., 1S87, 2 pp. 



