ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 261 



Disease of the Weymouth Pine.* — E. Hartig attributes the 

 disease to which this pine is so liable in Germany to the fact of the 

 thinness of its cork-layer, owing to its native habitat, the boggy 

 lowlands of North America. It is therefore unable to resist the very 

 high transpiration from the heat of the sun in Central Europe, which 

 results in the drying up of the bark and cambium, especially on 

 the southern and western sides, thus rendering the trunk extremely 

 subject to the attacks of fungi, such as Agaricus melleus, Coleosporium 

 Senecionis, and Trametes radiciperda. 



Flora of Spitzbergen.j— A. G. Nathorst gives the following as 

 the main results of two visits to Spitzbergen in 1870 and 1882 : — 



1. The flora of Spitzbergen is richer than that of any other 

 country of the same latitude, except possibly Grinnell-land ; and it 

 is probable that there are still vascular plants remaining to be 

 discovered. 



2. The larger part, at all events, of the Arctic flora avoids the coast, 

 and attains its richest development in the most continental regions. 



3. During the glacial period, only a very few species, if any, 

 could have maintained themselves in Spitzbergen ; most or all of those 

 which now constitute its flora must have migrated there during the 

 post-glacial period. 



4. About 75 per cent, of the vascular plants flourish there and 

 produce seeds. These are probably the species which migrated first. 



5. The remainder, mostly bog- and shore-plants, are the survivors 

 of a portion of the post-glacial period when the climate was warmer 

 than it is now; these migrated later than the others. 



6. The migration of the Spitzbergen flora took place over land, 

 with perhaps a few exceptions. 



7. This land formed a now submerged connection between 

 Spitzbergen, Nova Zembla, Arctic Eussia, and Scandinavia, from which 

 countries the flora is derived. 



8. No interchange with Greenland took place during the quater- 

 nary period, except perhaps accidentally. 



B. CRYPTOGAMIA. 



Cryptogamia Vascularia. 



Fructification of Fossil Ferns.t— E. Zeiller has examined and 

 described a large number of ferns from the "terrain houiller," 

 where they are very abundant, though the fructification is compara- 

 tively rare. From the remains which he has been able to examiae, 

 chiefly from the Pas-de- Calais, he gives detailed descriptions of the 

 following genera : — 



I. Sporangia grouped into a synangium, and partially united : — 

 Marattiace?e. Sporangia without annulus. Genera :— Crossotheca n. g. — 



* Unters. aus d. Forstbot. Inst. Munchen, iii. (1883) pp. 145-9. See Bot 

 Centralbl., xvi. (1883) p. 304. 



t K. Svensk. Vetensk.-Akad. Handl., xx. (1883). See Naturforscher, xvi 

 (1883) p. 457. 



X Ann. Sci. Nat. (Bot.), xvi. (1883) pp. 177-209 c4 pis.). 



