ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
647 
Prof. B. D. Halsted * describes a new species of Zygodesmus , 
a genus of fungi which is usually saprophytic, truly parasitic on a 
species of Viola. 
British Hymenolichen. — Mr. C. H. Wright remarked at the April 
meeting of the Society : — “ In Berkeley’s Mycological Herbarium, now 
at Kew, there exists a plant collected at Coed Coch, North Wales, in 
1866, which had been placed by Berkeley with Stereum hirsutum Fr., 
a fungus to which it bears a considerable amount of external resemblance, 
which is intensified by the latter being frequently infested by small 
algae, e. g. Chlorococcus, & c. Upon microscopical examination this plant 
proves to be Dictyonema sericeum Mont. ( Dichonema sericeum Fr.), a 
hymenolichen of frequent occurrence in the tropics of both hemispheres. 
In ‘ English Botany,’ Supplement, t. 2954, is figured a plant under 
the name of T&hizonema interruptum Thw., which, as Bornet f has 
suggested, is identical with Dictyonema sericeum Mont. This figure is 
repeated in Cooke’s c British Freshwater Algae,’ p. 266, 1. 106, f. 2, where 
Calothrix interrupta Carm. is added as a synonym, with a note to the 
effect that £ we have seen no specimen of this.’ Carmichael’s specimen 
agrees perfectly with the ‘ English Botany ’ figure, as does also a specimen 
from Machynlleth (the original ‘ English Botany ’ locality) in Berkeley’s 
herbarium. A similar specimen has been collected at Killarney. Both 
Carmichael and Hassall omit the colourless hyphae in their figures, and 
class the plant as an alga. 
The British localities for this species are : — Machynlleth (Ralfs) ! ; 
Coed Coch (Berkeley) ! ; Bristol ; Wareham ; Appin (Carmichael) ! ; 
Killarney ! ” 
Chromogenic Pseudo-Yeasts.| — Under the name “ formes-levures ” 
M. E. Laurent designates certain fungi which resemble true yeasts, but 
which are devoid of the fermentative faculty. In common with certain 
bacteria, these pseudo-yeasts possess the power of producing colouring 
matter. The oldest designation was Saccliaromyces glutinis , a name which 
embraced many different kinds. They are extensively distributed in air 
and water, grow on boiled potato when exposed to air, and are much 
more frequent than Micrococcus prodigiosus , with which they may be 
easily confounded. 
After recalling the fact that certain kinds of these organisms are 
found to produce a red, black, and violet pigment, the author narrates the 
life-history of a pseudo-yeast which developes a yellow colour. In most 
of its characteristics it was found to resemble Dematium pullulans, from 
which it only differs in its colour, its inability to liquefy gelatin, and in 
the fact that the older cells do not become embrowned. The author 
therefore considers this yellow pseudo-yeast to be a new variety of 
Cladosporium herb arum, a fungus remarkable for its polymorphism, and 
from which Dematium pullulans is descended. 
Influence of Concentration of Nutritive Medium on Growth of Fungi.§ 
• — Herr P. Eschenhagen finds, from his experiments with various nutritive 
* Bull. Torrey Bot. Club, xvii. (1890) pp. 151-2. 
t Ann. Sci. Nat., ser. 5, xvii. p. 82. 
X CR. Soc. Roy. Bot. Belgique, 1890, pp. 76-9. 
§ Ber. Yerhandl. R. Sachs. Gesell. Wiss., 1890, pp. 843-6. 
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