392 BOTANICAL GAZETTE [November 



of zinc for its maximum growth than does the latter. He beUeves that the 

 variation in zinc optimum found by different workers for this species can be 

 explained in part by the difference in the strains, and in part by the difference 

 in the composition of the cultural vessels used. He thinks that pyrex glass, 

 if free from zinc, may bear other substances that stimulate slightly, and that 

 gradual dissolution of these from the glass may account for the continual 

 decrease in yield when cultures are repeated many times in the same flasks. 

 He also admits that other unknown factors may account for this. He thinks 

 it probable that this species has never been grown in total absence of zinc. — 

 Wm. Crocker. 



Multiple eggs in bryophytes. — Florin,'' studying the archegonium of 

 Riccardia pinguis, finds the axial row very variable. One archegonium con- 

 tained an axial row of 4 cells, all of which had developed into eggs; another 

 contained a single egg, 2 ventral canal cells, and 2 rows of neck canal cells; still 

 another contained 4 eggs in the venter after the canal cells had completely 

 disintegrated. Such so-called abnormalities are frequent in bryophytes, 

 making it increasingly clear that both the antheridium and the archegonium are 

 derived from a common gametangium, and that the archegonium occasionally 

 reverts to that time when multiple eggs were the rule instead of the exception. 

 Some mosses revert to a time still more distant, a time when both male and 

 female gametes were present in the same gametangium, since we occasionally 

 find both spermatogenous and oogenous cells in the same sex organ, which 

 usually has the external form of an archegonium. — W. J. G. Land. 



Tyrosinase of fungi. — Dodge^ has made a very careful chemical study of 

 the action of tyrosinase on tyrosin. He obtained his enzyme from Daedalis 

 conjragosa, Armillaria mellea, and Polyporus sulphtireus. He finds (i) that 

 the tyrosin molecule is not deaminized, and (2) that in the formation of the 

 colored compounds the tyrosin molecules are combined into larger molecules, 

 accompanied by the masking of the carboxyl groups. — ^J. J. Willaman. 



Absorption of gold. — The ability of Penicillium glaucum and Oidium lactis 

 to develop from conidia in colloidal gold solutions to which tannic acid or 

 gum arable has been added has been studied by Miss Williams.^ The 

 coUoidal gold is slowly removed from solution during growth, removal being 

 effected by the uncuticularized walls. The gold did not enter the protoplasm. 

 No satisfactory explanation of the phenomena was found. — C. A. Shull. 



1 Florin, Rudolf, Das Archegonium der Riccardia pinguis (L) B.Gr. Svensk. 

 Bot. Tidskr. 12:464-470. figs. 4. 1918. 



s Dodge, C. W., Tyrosin in the fungi: chemistry and methods of studying the 

 tyrosinase reaction. Ann. Mo. Bot. Gard. 6:71-92. 1919. 



<• Williams, Maud, Absorption of gold from colloidal solution by fungi. Ann. 

 Botany 32:531-534. 1918. 



