Physiologie. — Palaeontologie. 
243 
coside d’une autre faqon. Le titre du memoire anglais de 1906 est de 
nature ä laisser supposer que la decouverte du glucoside du Lin est 
posterieure ä celle de la phaseolunatine. 
Cette note de A. Jorissen est suivie, dans le meme recueil aca- 
demique, d’une note sans titre de A. Gilkinet rappelant, notamment, 
que, lorsque Runge a decouvert la cafeine en 1820, il n’a pas 
meme donne la composition de cet alcaloide. Celle-ci n’a ete deter- 
minee que douze ans plus tard par Liebig et Pfaff; cependant les 
noms de theine, de guaranine, etc., donnes ulterieurement aux al- 
calbides du the et de la päte de guarana, ont ete abandonnes 
aussitöt qu’il a ete demontre que ces alcaloides etaient identiques ä 
la cafeine. Henri Micheels. 
Bather, F. A., Nathorst’s use of Collodion Imprints in the 
study of Fossil Plants. (Geol. Mag. Vol. IV. p. 437—440, with a 
text-figure, Dec. 5, 1907.) 
A short account of the new method, applied by Nathorst to 
the study of fossil plants, which consists in making a thin collodion 
film on the surface of a fossil impression or petrifaction, which on 
removal, can be mounted and examined microscopically. 
Arber (Cambridge). 
Benson, M., Miadesmia membranacea Bertrand, a new Palaeo- 
zoic Lycopod with a Seed-like Structure. (Proc. Roy. Soc. 
London, Vol. LXXIX. p. 473. 1907.) 
Miadesmia is exceedingly minute, its stem slender, and without 
any trace of skeletal tissue. Is is the first Palaeozoic Lycopod of 
herbaceous character, known structurally. The megasporophylls show 
a more advanced type of seed habit than has hitherto been met 
with in Cryptogams. The megasporange gives rise to but one thin- 
walled Spore, which in development and structure resembles an 
embryo-sac and germinates in situ. An integument surrounds the 
sporange, having but a small orifice or micropyle. This is surrounded 
by numerous long processes of the integument. There is no trace 
of an envelope about the microsporange. The earpellary leaf was 
shed at maturity and resembles a winged seed. The nearest afhnity 
of Miadesmia appears to be with the non-specialised species of 
Selaginella , such as 5. selaginoides, but the foliage leaves show the 
archaic leaf-base comparable with that of Lepidodendreae. 
Arber (Cambridge). 
Henslow, G., On the Xerophytic characters of certain Coal- 
plants and a suggested origin of Coal-beds. (Quart Journ. 
Geol. Soc. Vol. LXIII. p. 282—290. 1907.) 
The author points out that the anatomical structure of coal 
plants exhibits hygrophytic as well as strong xerophytic characters 
in various genera. Xerophytic characters are seen in the reduced 
leaves of a Calamite, a genus on the whole decidedly hygrophytic. 
He then explains the presence of xerophytic features in the trees of 
the fresh water marshes of the coal period as due to their migration 
from dry situations, for fresh water never gives rise to xerophytic 
structures. Where such migration takes place the form or external 
morphological features are retained but (wherever necessary) the 
anatomy is changed. With the exception of the Equisetales, the 
other plants of the coal flora show chiefly xerophytic characters, 
