NOTES AND ABSTRACTS. 



333 



those plants grown in soils containing this salt, but'there were remark- 

 able differences in the proportions of the other minerals taken up. 



In some cases the plants on manganiferous soil absorbed double the 

 amount of lime, and only half that of the magnesia and phosphoric 

 acid, taken by those which were grown in normal soils. 



But there are in the tables given extraordinary variations. Out 

 of twenty-six plants, in three cases less lime was absorbed, in ten more 

 magnesia, and in two cases more phosphoric acid in the manganiferous 

 soil. 



The author infers that soluble manganese, when reaching the root- 

 hairs, is absorbed and forms combinations with the protoplasm. Once 

 these combinations are formed, the permeability of the protoplasm is 

 altered, and this affects the relative absorption of lime and magnesia. 



Hence, as the balance of lime and magnesia is affected, some plants 

 may be assisted, others poisoned, and yet others maybe quite unaffected. 



Manganese may also act indirectly on plants by increasing oxidation 

 in the soil. There is also a possibility that phosphoric acid might be 

 precipitated in the soil as manganese phosphate, so hindering the 

 absorption of phosphoric acid. — G. F. S. E. 



Manganese on Pineapple Plants, Effect of. By E. V. Wilcox 

 and W. P. Kelley {U.S. Exp. Stn., Haw., Bull. 28, September 1912). — 

 Highly manganiferous soils cause the decay of roots, loss of chlorophyll, 

 bad ripening, with a formation of lime oxalate in the soil in large 

 quantities. The addition of soluble phosphates considerably modifies 

 the bad effects, and the authors recommend the planting of old stumps 

 instead of new suckers. — C. P. C. 



Mango: The Basis of Classification, By F. W. Popinoe [Am. 

 Pom. Soc, Bull. 7, p. 41). — The great confusion in the nomen- 

 clature of this fruit has led the author to propose a systematic descrip- 

 tion and a classification based first on the fact that mangos are 

 both monoembryonic and potyembryonic. The subsequent divisions 

 would be based on certain well-known geographical types, and a short 

 bibhography is appended. — E. A. Bd. 



Melanose and Stem-end Rot. By B. F. Floyd and H. E. Stevens 

 [U.S.A. Exp. Stn., Florida, Bull, iii ; 1913). — Experiments carried on 

 by the authors of this bulletin have clearly shown that melanose and 

 stem-end rot of citrus fruits are caused by one and the same fungus, 

 Phomopsis citri. Melanose is only a superficial spotting of fruit and 

 stems, whereas stem-end rot is a bad rot which occurs at the stem-end 

 of the citrus fruits and progresses down into the fruit itself, making 

 it valueless. 



Phomopsis citri can live as a saprophyte on dead twigs, which form 

 a dangerous source of infection to the surrounding branches. The 

 pycnidia are black ; the spores, which are oval, are protruded from 

 th2 pycnidia either as slimy masses or thread-like tendrils, and are 



