500 EDWARD A. BURT ON A 



the chambers by the formation of a gas within them. 1 This idea has found its way into 

 the text-books. 2 Such an explanation of the phenomenon has been objected to, and very 

 properly so, by Fischer in a short paper of great importance. 3 



In this article Fischer points out that the chambers are not surrounded by air-tight 

 walls ; that all of the chambers are open on one side in some of the forms which he has 

 studied; and that there is no visible indication of the inflation of the chambers during 

 their elongation. From these facts he concludes that the walls are not passive in their 

 straightening out, as De Bary's explanation necessitated. 



That they are the active agents he deduces from the forms of the cells at the ends of 

 the folds and from their changes in form when the folds straighten out. He shows that 

 at the inner angle of the fold the cells are wedge-shaped as if by compression, while on 

 the periphery of the fold they are elongated and thin as though stretched out there. 

 Upon placing such folds in certain aqueous solutions of slight density, the turgescence of 

 the cells increases by absorption of the liquid, they become more nearly spherical, and 

 the effect of such change of form both at the inner angle of the fold and at its periphery 

 is to straighten out the fold. 



In Anthurus borealis the cells of the folds have the forms which Fischer figures and 

 the folds straighten as he states. As the elongation of the stipe in plants of this sort 

 occurs only in wet weather or in damp places, it seems to me that Fischer has offered the 

 true explanation of the rapid elongation of the stipe — so rapid as to give rise to the 

 popular impression that such plants attain their full growth in a night. 



The Hymenium . 



It has been stated that the hymenial layer lines the chambers of the gleba. The 

 hyphae of the trama give off numerous short lateral branches, the swollen ends of which 

 form the hymenial layer (A, Figs. 17 and 20). In the youngest egg of Anthurus these 

 swollen ends were unsegmented and did not yet bear spores, and they stained deeply with 

 the carmine. In the later stages spores were present, and the deeply stained and swollen 

 but nevertheless comparatively small and slender ends of the tramal branches were 

 divided into four or five short cells and constricted at the septa (Fig. 11). 



It may be urged that the end cell of this series should be regarded as the true 

 basidium, but the preparations do not favor such a view. The figure was carefully made 



1 De Bary : Beitr. z. morph. u. physiol. der pilz'e, I., Eug. trans., p. 341. (c) Goebel : Outlines of classif. and 

 p. 202 and 207. spec, morph., Eng. trans., p. 139. 



J Ed. Fischer : Bemerk.. liber den streckungsvorgaug 



2 (a) DeBary: Comp. morph. of the Fungi, etc., des phalloideen-receptaculums. Mittheilungen der natur- 

 Eng. trans., p. 323. (6) Sachs: Text-book of botany, forschenden gesellschaft in Bern, 1887, p. 142-157. 



