574 SUMMARY OF CURRENT RESEARCHES RELATING TO 



axis which is itself a branch of a male stem. If dicecism occurs at all 

 in the species it is very rare. 



Multiple Chromatophores in Anthoceros.* — D. H. Campbell 

 collected in Java an Anthoceros which showed frequent instances of 

 double chromatophores in the superficial cells and multiple chromato- 

 phores in all the inner cells. The plant has spiral elaters, and no 

 stomata in the sporophyte, thus approaching more to Dendroceros ; but 

 the thallus is that of a typical Anthoceros. The solitary antheridium 

 and the presence of chlorophyll in the ripe spores recall Dendroceros. 

 Perhaps an intermediate genus will have to be founded. 



Spores of Riccia glauca.f — R. Beer has studied the development 

 of the spores of Riccia glauca in the light of modern methods, and adds 

 to the facts established by the researches of Leitgeb, Strasburger, G-arber, 

 and Lewis, upon other species of the genus. He describes the delicate 

 primary membrane that separates off the spore-mother-cells from one 

 another, and its secondary thickening layers, the mucilaginous degenera- 

 tion which the latter partly undergo when the spore-mother-cells round 

 themselves off and separate ; the absence of food material between the 

 separated mother-cells ; the structure of the resting nucleus of the 

 mother-cell, its nucleolus, chromosomes, and division phenomena ; the 

 primary membrane of the daughter-cells and its subsequent thickening, 

 its cuticularisation and lamination ; the callose plugs of mucilage at 

 the equatorial rim ; the nature of the endospore ; the active part played 

 by the protoplast in forming its membranes ; the source of the material 

 used for wall-formation ; the doubtful origin of the mucilage among the 

 spore-tetrads. 



Gemmae of Amblysteg-ium.J — C. Warnstorf describes the vegetative 

 reproduction of Amblystegium densum Milde, the history and relation- 

 ships of which he briefly sketches. Juratzka called attention to the 

 pro-embryo threads on the leaf-points, and rhizoids on the back of the 

 costa Limpricht regarded the produced leaf -apex as being only a 

 rhizoid. Warnstorf now points out that the threads on the back of the 

 costa are true rhizoids having oblique transverse walls, while those 

 arising from the leaf-apex are true protonema with transverse walls 

 placed at right angles. The rhizoids are much branched, pale, yellowish, 

 and warty ; they occur in clusters on creeping stems of a fragile nature. 

 The real reproductive organs, the true protonema threads are simple, 

 filamentous, yellow, smooth, subclavate, about 1 6 //. thick, and arise from 

 initial-cells on the back of the leaf point, and are easily detached. 



Monstrous Peristomes.§ — I. Hagen writes an historical note on 

 " acrosyncarpie renversee " in mosses. In the previous number of 

 " Hedwigia," Monkemeyer had described and figured for Dicranella 

 varia and Bryum saxonicum some instances of abnormal supplementary 

 peristomes intercalated between the operculum and the normal peri- 

 stome, in the belief that such an occurrence had not been recorded 



* Ann. of Bot., xx. (1906) p. 322. t Tom. cit., pp. 275-91 (2 pis.) 



% Allg. Bot. Zeitschr., xii. (1906) pp. 106-8. 

 § Hedwigia, xlv. (1906) pp. 239-40. 



