774 SUMMARY OF CURRENT RESEARCHES RELATING TO 



in tho spring formcil a number of new shoots. After growing under 

 water the moss exactly resembled a sub-lacustrino variety of T. alope- 

 curum, which grows at a depth of 200 metres in the Lake of Geneva. 

 On examining the young shoots, brown filaments which were formed of 

 cells with oblique septa were seen. On those filaments or rhizoids 

 gemma) were developed. 



Protonema of Schistostega osmundacea.* — Herr F. Noll describes 

 tho mode of vegetative reproduction of the protonema of this moss, and 

 explains its shining appearance by its peculiar construction, which causes 

 its lenticular cells to concentrate all the light tliat falls upon them on 

 their posterior wall, and to illuminate intensely the chloropliyll-grains 

 which collect on these walls. The rays which enter these colls in a 

 parallel direction are so reflected that tliey again emerge parallel or 

 slightly convergent, by which the bright shining appearance is brought 

 about. 



Physiological and Comparative Anatomy of Sphagnaceae-f — In 

 this treatise Ilerr E. Eussow treats especially of the anatomy of the 

 leaves of Spliagnum from a physiological point of view. He shows that 

 not only the leaves on both the erect and the pendent branches, but also 

 the separate parts of the leaf, are adapted, by their structure, to the 

 various requirements as regards firmness. This firmness is chiefly secured 

 by the stiffening of the hyaline cells by means of annular and spiral 

 fibres. These occur in all the cells of the leaves of the pendent branches, 

 and in those of the basal half of the cells of the erect branches, in the 

 form of bands projecting slightly into the cell-cavity. In the cells of 

 the upper half of the leaves on the erect branches there are, on the other 

 hand, a larger or smaller number of broad stiffening plates or bands 

 placed at right angles to the cell-wall. The diameter of these plates at 

 right angles to the cell-wall decreases from the apex towards the base 

 of the leaf. It is chiefly by these plates that the surface of the 

 leaf becomes folded in ; they run across the leaf, and are united by 

 anastomoses running in the direction of the length of the leaf. The 

 leaves belonging to the fertile stem and branches, which are usually 

 completely concealed, have no similar stiffening-bands ; they consist 

 simply of uniform chlorophyllous cells, their main function being the 

 nutrition of the sporogonium. The pseudo-fibres of the stem-leaves must be 

 distinguished from the true fibres of the hyaline cells, being nothing 

 more than portions of cell-wall which remain behind between the orifices 

 resulting from resorption. The pores of the hyaline cells have, in all the 

 species which do not permanently live in water, their margins strongly 

 thickened in a peculiar way, for the purpose of preventing the rupture 

 of the margins, and in order to facilitate the absorption and the retention 

 of water. The stiffening-bands increase the inner surface of the hyaline 

 cells, and hence their capillary power. The position of the cLlorophyll- 

 cells is determined by the necessity of protection from light. Either on 

 both sides or on the one most exposed to the light they are partially or 

 entirely covered on both sides by the hyaline cells. When this is not 

 the case, the free walls of the chlorophyll-cells are imbricately apicu- 



* Ycrsamml. Deutscher Naturf. u. Aerzte, Wiesbaden, Sept. 21, 1887. See Bot. 

 CeDtralbl., xxxiv. (1888) p. 399. 



t ' Zur Anat. resp. physiolog. u. vergleich. Anat. d. Torfmoose,' 35 pp. and 

 5 pis., Dorpat, 1887. See Bot. Ztg., xlvi. (1888) p. 335. 



