596 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
H. Potonie comes to the conclusion that the stages of development may- 
be represented by the following series : — Sphenophyllnm , Trizygia , 
Salvinia. Azolla. This hypothesis is corroborated by the evidence of 
geology. 
Muscineae. 
Anatomy of Mosses. * — Herr W. Lorch has studied the structure of 
those mosses which agree with the Sphagnaceae in possessing, in their 
leaves, hyaline empty cells with perforated walls, viz. the Leucobryaceae, 
and certain genera of Pottiaceae, Calymperes, Syrrhopodon, and Encalypta. 
The leaves of the Leucobryaceae ( Artlirocormus , Leucobryum, Leuco- 
phanes , Octoblepharum , Schistomitrium , Spirilla) differ from those of 
Sphagnum in having several layers of cells. In Leucobryum v nig are the 
hyaline cells occupy several layers, the chlorophyllaceous cells only one. 
The two kinds originate at the same time, the chlorophyllaceous cells 
attaining ultimately a much larger size than the hyaline. The former 
are connected with one another by longer or shorter prolongations. 
They do not divide after being once formed. In the Pottiaceae with 
hyaline cells these constitute only a single layer, and this is confined to 
the basal portion of the leaf. The upper portion of the leaf is com- 
posed of chlorophyllaceous cells, mostly isodiametrical and more or less 
papillose. 
The hyaline cells serve for the absorption and storing up of water ; 
the Leucobryaceae and the genera of Pottiaceae named growing on rocks, 
the trunks of trees, and other dry situations. The same service is per- 
formed by the papillae of the chlorophyllaceous cells, and by the hyaline 
hairs and apices of the leaves in other mosses. 
Venation of the Muscineae.j — M. F. Morin has undertaken an 
exhaustive examination of the venation in different families of Muscineae ; 
the degree of complication of which he finds in some cases characteristic 
of species, in others of genera or tribes. There is no general distinction 
between the venation of the Musci and that of the Hepaticae. In some 
cases it is more complicated than that of some aquatic flowering plants. 
Physcomitrium.J— Mrs. E. G. Britton gives a monograph of the 
American species of this genus of Musci, including descriptions of five 
new species, P. australe, Kellermani, Drummondii , coloradense , and call- 
fornicum. 
Kabenhorst’s Cryptogamic Flora of Germany (Musci). — The last 
two parts published of this portion of Rabenhorst’s great work (22 and 
23) complete the account of the Meeseaceae with the monotypic genus 
Catoscopium, and then describe the species of the following families : — 
Aulacomniaceae (3 sp. of Aulacomnium) ; Bartramiaceae ( Plagiopis 1 sp., 
Conostomum 1 sp., Bartramia 7 sp., Brentelia 1 sp., Philonotis 11 sp.) ; 
Timmiaceae (4 sp. of Timmia ) ; and Polytrichaceae ( Catharinsea 5 sp., 
Pogonatum 5 sp., Polytrichum 11 sp., Oligotrichum 1 sp., Psilopilum 1 sp.). 
The Buxbaumiaceae are commenced with the genus Buxbaumia. 
* Flora, lxxviii. (1894) pp. 424-65 (35 figs.). 
f ‘ Anat. comp, et exp. de la fam. des Muscine'es,’ Rennes, 1893, 139 pp. and 
24 pis. See Bot. Centralbl., lviii. (1894) p. 164. 
I Bull. Torrey Bot. Club, xxi. (1894) pp. 189-207 (7 pis.). 
