ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1027 



stance serves as the matrix. The characteristic reaction is a blue 

 colour with sulphuric acid, and green with potassium biniodide. To 

 this class belongs also the red pigment in the latex-tubes of Lactarius 

 deliciosus, while the green colour of the pileus is due to a pigment of 

 the second description. Coloured substances occur also in the hypha) 

 of many fungi. 



In about 30 species of fungus, the author found seven red, three 

 violet, and five yellow pigments. The number appears to be greater 

 than in the petals of flowering plants. Many species seem to be dis- 

 tinguished by a specific pigment, while other colouring matters are 

 common to several species of a genus or to a number belonging to 

 different genera. 



Edible Fungi.* — Herr C. J. Morner has made a careful estima- 

 tion of the nitrogenous contents of the various edible fungi, distin- 

 guishing between those albuminous constituents which are, and those 

 which are not digestible. The result is materially to reduce the 

 nutritious properties of these plants below the estimate previously 

 held. The fungi containing the largest proportion of digestible al- 

 buminoids are Agaricus campestris, 22 ■ 3 per cent, of the dry weight, 

 Lycoperdon bovista, 19 '2 per cent., and Agaricus procerus, 18 • 7 per 

 cent. ; next to these come Morchella esculenta and Boletus edulis and 

 scaber. In these species the indigestible albuminoids vary from 4 ■ 

 to 16*7 per cent. ; while in some other species they are considerably 

 in excess of the digestible nitrogenous constituents. 



Structure and Development of Ascomycetes.f — Herr H. Zukal 

 describes the fructification of Thelebolus stercoreus, growing on hare's 

 dung, and determines that it belongs to the Ascomycetes rather than 

 the Gasteromycetes, placing it among the Erysipheaa near to 

 Podosphsera. It is distinguished by the yellow colour of the perithecia 

 which burst when placed in water, the single ascus being projected 

 into the air. The mechanism of expulsion is as follows : — At the 

 base of the sporiferous sac is an accumulation of substance capable of 

 absorbing a great quantity of water ; the water enters this through the 

 upper part of the membrane of the ascus, which is very permeable ; 

 the ascus in consequence increases greatly in volume and bursts the 

 perithecium. The ascus is also remarkable for the great number of 

 spores which it contains (probably 8 x 64). 



From a study of the development of the fructification of Ascodesmis 

 nigricans, Hyplwmyces rosellus, Chaetomium crispatum, and Eurotium 

 herbariorum, Zukal draws conclusions opposed to the sexuality of the 

 Ascomycetes. 



In Eurotium herbariorum he finds asci developed quite inde- 

 pendently of the archicarp and pollinodium, describod by de Bary as 

 the sexual organs. 



Ascodesmis nigricans, which grows on dogs' excrements, Zukal 

 regards as a transitional form between the Gymnoasci and the 



* Bot. Sekt. Naturvet. Studeuts'allsk. Upsala, April 13, 1886. See Bot. 

 Centralbl., xxvii. (1886) p. 130. 



t Denkschr. Malh.-rjatnrwiss. Classe Akad. Wiss. Wien, 1S85. See Bull. 

 Soc. Bot. France, xxxiv. (1886) Rev. Bibl., p. 51. 



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