ZOOLOGlf AND BOTANY, MICROSCOPY, ETC. 421 



Helicosporanginm parasiticum has been found especially on carrots. 

 The mycelium branches copiously, the ends of the branches coiling 

 like a watch-spring, a second spiral often springing from the stalk 

 of the first, and becoming closely united with it in growth. The 

 spirals become septated, and a central cell is separated, which 

 increases considerably in size, becomes brownish red and densely filled 

 with protoplasm, while the cortical cells are nearly empty, the 

 central cell only germinating. The fungus produces also conidia. 



PapuUspora aspergilUformis is found on all kinds of decaying 

 substances, such as stems, seeds, fruits, tubers, &c., forming a delicate 

 white coating, which is soon covered with the brownish red clusters 

 of spores. The mode of reproduction is by conidia resembling those 

 of Aspergillus ; but the fungus also produces very peculiar reproductive 

 bodies, which are called bulbils by the author. It also produces 

 chlamydospores. 



Fungi Parasitic on Forest-trees.* — In continuation of previous 

 investigations, E. Eostrup gives the following account of the parasitic 

 fungi most destructive to forest-trees in Denmark. 



Melampsora salicina. The author confirms the statement of Nielsen 

 that the species of Melampsora found upon willows belong to the 

 heteroscious Uredinese, and that Cceoma Mibesei and Euonymi are their 

 aecidial forms, while G. Mercurialis is the secidial form of M. Tremulce.. 



Peridermium Pini eorticola, the vesicular sBcidial form of poleo- 

 sporium Senecionis, has been of late years very destructive to Pinus 

 Strohus in Denmark, completely destroying plantations from five to 

 twenty years old. Since the Eecidial form cannot propagate itself 

 from tree to tree, while Coleosporium will maintain itself from year 

 to year, the complete destruction of Senecio sylvaticus would be an 

 effective way of eradicating the pest. 



Cceoma pinitorquum often makes its appearance in large quantities 

 on young plantations of various species of pine on the heaths of 

 Jutland. G. Laricis has also found its way into Denmark, attacking 

 the European and American larches since 1881. 



Agaricus melleus sometimes destroys as much as 25 per cent, of 

 the young pines in the Jutland plantations, rhizomorphs more than 

 11 feet long having been dug out of the ground ; they attack and 

 completely destroy felled trunks of oak or ash lying on the ground. 

 Eostrup gives a list of twenty-four species of tree which this destruc- 

 tive parasite attacks. 



In older plantations of conifers, still greater injury results from 

 the attacks of Trametes radiciperda, which also occasionally seizes 

 upon young trees. 



Polyporus fomentarius is a true parasite, the mycelium of which 

 permeates the entire duramen of beech-trees, attacking them when 

 quite healthy. P. betulinus is also injurious to birch- trees ; and 

 P. nigricans is found in a half-fossil condition on the trunks of Betula 

 alba buried in turf-mosses. 



* Miiller's Tidsskr. for Skovbrug., vi. (1883) pp. 199-300 (17 woodcuts). See 

 Bot. Centralbl., xv. (1883) p. 147- 



