542 SUMMAKY OF CUERENT RESEAECHES RELATING TO 



supports the view that chemical poisons or ferments play an important 

 part in the injections connected with organic germs. 



Lichenes. 



Life-history of Cora.* — The genus Cora, established by Fries, 

 has been regarded by some as belonging to Algae, by others as belong- 

 ing to Fungi, while Nylander, who detected the true fructification 

 as consisting of apothecia and ascospores, maintained it to be a lichen. 

 O. Mattirolo has carefully examined all the known species, and fully 

 confirms Nylander's view. 



In the thallus is a well-defined gonimic layer, the gonidia 

 belonging to the genus Chroococcus. One species, Cora ligulata 

 Kremp., must be erected into a distinct genus in which the gonidia 

 have a Scytonema-fovm ; Mattirolo proposes for it the name Bhipido- 

 nema. The author has not been able to confirm Nylander's account 

 of the occurrence of apothecia, which probably belonged to a different 

 lichen or fungus. Both Cora and Bhipidonema have on the under 

 side a true hymenium, something like Thelephora or Kneiffia, formed 

 of basidia which are the apices of special hyphae. Each basidium 

 bears a sterigma, on which is a single spherical spore, as in Kneiffia. 



The author holds, therefore, that we have in these two genera 

 lichens in the building up of which Basidiomycetes, and not Ascomy- 

 cetes, have taken part. This new group he terms Hymenolichenes, 

 and places them among the Basidiomycetes, near to Kneiffia, Corticium, 

 Stereum, Thelephora, and Hypochnus. It includes the following 

 species : — Cora Pavonia, glabrata, gyrolopliia, and Neesiana, and 

 Bhipidonema ligulata. They are all extra-European, and abundant 

 in the tropics. 



Minks' s Licheno-mycological Symbols, f — In his last essay on the 

 structure and affinity of lichens, Dr. A. Minks recapitulates the 

 grounds of his microgonidial theory,:}: and recommends Leptogium 

 myochroum as a specially favourable species for establishing the 

 existence of microgonidia. The ascus of a lichen he regards as 

 simply a highly differentiated hypha, the terminal cell of which has 

 the power of dividing so as to produce the spores. Neither in the 

 history of their development nor in their structure do the spores 

 correspond to the ascospores of the true Ascomycetes ; and their 

 mode of germination is also different. 



The portion already published of Dr. Minks's work includes 

 descriptions of 170 species ; and the whole family is intended to be 

 gone through at the rate of about 200 species per annum. 



Algse. 



Symbiosis of Algse with Lower Animals.§ — Since so many 

 naturalists have published observations on this subject, Dr. G. Entz 



* Nuov. Giorn. Bot. Ital., xiii. (1881) pp. 245-67 (2 pis.), 

 t Minks, A., ' Symbolse licheno-mvcologicse,' Part I. Cassel, 1881. 

 X See this Journal, ii. (1879) pp. 311, 931. 



§ Biol. Centralbl., i. (1881) p. 646. Cf. Naturforscher, xv. (1882) pp. 93-4, 

 and this Journal, ante, p. 241. 



