752 SUMMARY OF CURRENT RESEARCHES RELATING TO 



not brought together by cell fusion, but of more or less independent 

 ancestry. 4. The fusion of gametes without the fusion of their nuclei, 

 the latter reproducing by conjugate division for long series of cell 

 generations, and finally fusing just before the reduction division. 5. 

 Fertilization by nuclear migration from a vegetative cell to an egg or 

 fertile cell. 6. Two successive fusions in the same life cycle, a normal 

 conjugation of gametes and later endokaryogamy. 



Plant Diseases.* --F. von Faber describes galls on the roots of 

 seedlings of Kickxia elastica, that destroyed them. Microscopical 

 examination showed that the galls were caused by a fungus which 

 evidently excreted some poison that caused the cells to swell up to an 

 enormous size and form galls. It was impossible to classify the fungus, 

 as no fruit was formed. 



F. Gueguen t describes a- disease of the fruits of cacao caused by a 

 mould, the infection having been conveyed by an insect which had bored 

 into the fruit. The fungus is nearly related to Acrostalagmus : occa- 

 sionally it enters the fruit along with the pollen tubes. The seeds are 

 not affected internally, but they are overgrown by the mycelium of the 

 fungus. 



Keith Bancroft % has published, in book form, an accouut of the 

 fungoid diseases of tropical plants, more especially of those that occur in 

 the West Indies. Diagnoses and general descriptions of the fungi are 

 given, and references to original literature bearing on them. In the 

 introduction Bancroft discusses the various methods of treating disease. 



G. Lustner § writes of the damage done to apples and pears by the 

 mildew Podosphsera leucotricha Salm. It was first detected by Sorauer 

 in 1884, since then it has spread widely : it destroys the young shoots 

 and leaves of apple trees. It spreads over the whole branch in pear 

 trees, and in some species attacks the fruit. Pruning the diseased 

 branches is strongly recommended. 



A. Naumann || reports several fungoid diseases of rhododendron, 

 Physalospora Rhododeiidri sp. n., which causes the leaves to wither from 

 midrib outwards, and Exobasidium, which was found forming the cha- 

 racteristic galls on Azaleas. It resembled strongly E. Vaccitm. 



A disease of strawberrylf leaves due to Ramularia TaJasnei is 

 described in the Journal of the Board of Agriculture. It forms spots 

 on the leaves, and considerably weakens the foliage. The perfect 

 fruiting form was unknown for a long time, but has now been deter- 

 mined as SpJiserella Fragarise, a minute Pyrenomycete. Spraying is 

 recommended to check the disease. 



Emile Mer ** publishes a long series of notes on the growth and 

 development of Lophodermium macrosporum on the needles of Epicea, 



* Ann. Mvcol., viii. (1910) pp. 449-51 (1 fig.). 



t C.R Soc. Biol. Paris, lxviii. (1910) pp. 221-22. See also Ann. Mycol., viii. 

 (1910) p. 485. 



X Handbook of the Fungus Diseases of West Indian Plants, 70 pp. (6 pis.). 



§ Jahresb. Ver. Angew. Bot., vii. (1909) pp. 106-11. See also Ann. Mycol., viii. 

 (1910) p. 484. 



|| Tom. cit., pp. 181-8. See also Ann. Mycol., viii. (1910) p. 484. 



1 Journ. Board Agric, xvii. (1910) pp. 476-7 (pi.). 

 ** Rev. Gen. Bot., xxii. (1910) pp. 297-335. 



