488 8UMMAKY OP CURRENT RESEARCHES RELATING TO 



In the Tremellineae the simultaneous production of both basidio- 

 spores is the rule, as in Dacryomyces and Tremella. The basidiospores 

 of AuricuZaria sambucina might just as well be called conidia ; and 

 the same is the case with those of Scleroderma Bovista, in which the 

 sterigma (basidium) is almost completely suppressed. Polyporus 

 zonatus produces conidia even on the hymenium on the under side of 

 the pileus in the tubes. The author failed in inducing any of these 

 conidia to germinate. 



When Agaricus tenerrirmis is grown in very moist situations, its 

 entire hymenial layer becomes transformed into one of conidia. While 

 still attached to the hyph^ these conidia will sometimes bud in a 

 torulose manner. Conidia are also produced on the upper surface of 

 the pileus. A.fimicola produces conidia close to and among the ripe 

 fertile basidia; they are borne both on the cystidia and on ordinary 

 hyphffi. They can be easily produced by growing on dung under a 

 watch-glass. A. rugosus furnishes an admirable example of the passage 

 of ordinary conidia into basidiospores, 



Endogenons Spore-formation in the Hyphomycetes.* — M. C. A. 

 J. A. Oudemans describes a species of Sporendonema found in a 

 green-house among tan, which he calls S. terrestre. The plant con- 

 sists of a mycelium with hyph® partly creeping, partly erect. In the 

 latter are formed endogenous spores, characteristic of the species. 

 Several are formed in each hypha, without the earlier being first 

 separated by septa. The separation of the spores from one another 

 and from the plant is effected by circular fissures which split the wall, 

 and which cause the hypha to break up into tubular pieces, open at 

 both ends, each of which contains a spore. 



Tnrgidity in Phycomyces.f — M. E. Laurent has investigated the 

 cause of the sudden stoppage of growth during the second and third 

 of Errera's four stages of growth | of the fructification of Phycomyces, 

 the period of formation of the sporangium and detachment of the 

 spores. The experimental test of the degree of tnrgidity employed 

 ■was the plasmolytic method of De Vries, the measure of the tnrgidity 

 within the cells of the fructification being the degree of concentration 

 of a solution of potassium nitrate which was sufficient to cause a con- 

 traction of the organ perceptible under the Microscope. By this 

 method it was shown that at the end of the first stage the zone of 

 cell-wall most capable of extension, which had hitherto been below 

 the apex, passed to the apex and swelled up into the sporangium, a 

 large quantity of nutrient material being used up in this process, so 

 that the growth of the sporangiophore ceased, and the power of 

 extension of its membrane had greatly decreased. The same was the 

 case during the third stage, while the spores were being formed. In 

 the fourth stage the excess of nutrient material again contributed 

 to the extensibility of the membrane of the sporangiophore and its 

 renewed increase in length. 



* Versl. Mtded. K. Akad. WeteDsch. Amsterdam, iii. (1885) pp. 115-22 (1 pi.)- 

 + Bull. Acad. Koy. Sci. Belgique, x. (1885) pp. 57-79. 

 J Hee this Journal, v. (1885) p. 288. 



