NOTES AND ABSTRACTS. 



291 



Leaves, Migration in, in Autumn {Jour. Soc. Nat. Hon. Fr., 

 4th Series, vol. xiii., p. 693, Nov., 1912). — Before falling, leaves turn 

 yellow. This arrest of activity corresponds to a migration of elements 

 in the plant, which phenomenon has been measured by a German 

 agriculturist in the leaves of fruit trees. He shows that the migration 

 begins on July 14 and ceases on Nov. 1. The diminution of the dry 

 remainder of the leaf is from 30 to 35 per cent. There is therefore an 

 active phenomenon, and not a simple desiccation. The potash, lime, 

 magnesium, and phosphoric acid, but not the silica, are thus returned 

 to the tissues of the tree. The nitrate goes back to it rapidly, as well 

 as the carbohydrates and organic acids. The leaf merely preserves 

 its cellular elements. When the cold comes too early the leaves fall 

 without this preliminary migration. These researches show what 

 mistakes may be made by agriculturists who supply additional 

 fertilizing elements after a calculation of the elements of the leaves 

 in a green state. It is necessary to wait for the fallen leaves 

 to appreciate the amount they are calculated to return to the 

 soil. — M. L. H. 



Leguminous Plants, Life-history of Aseochyta on some. By R. E. 



Stone {A nnal. My col., x., pp. 564-592 ; June, 1912 ; 2 plates). — 

 The author deals first with the fungus Aseochyta pisi, a troublesome 

 pest of culinary peas, showing that it is connected with the higher 

 form known as Sphaerella pinodes (Berk, and Blox.) Niessl. The 

 Aseochyta which grows on nutrient media from the spores of the 

 Sphaerella readily infects peas producing the characteristic spots. 

 In the same way he shows that A. viciae and 5. viciae are connected. 

 The two forms 5. pinodes and 5. viciae are shown to be identical, and 

 probably so also is that which occurs on the Everlasting Pea and on 

 the Sweet Pea. The new combination Mycosphaerella pinodes is 

 proposed for this species. Aseochyta lethalis on melilot is found to 

 be connected with a new ascochycetous fungus which the author 

 calls Mycosphaerella lethalis, Stone. — F. J. C. 



Leptospermum Scoparium Nichollii. By L. Roberts (Gard. Chron., 

 p. 270 ; October 5, 1912). — Gives the history of the origin of this red 

 form. — E. A. B. 



Lightning in Relation to Forest Fires. By Fred G. Plummer 

 (U.S.A. Dep. Agr., For. Serv., Bull. 111 ; Sept. 12, 1912). — A most 

 interesting and instructive report of lightning in relation to forest 

 trees, which may be summed up as follows : — The likelihood of a 

 tree being struck by lightning is increased (a) if it is taller than 

 the surrounding trees, (b) if isolated, (c) if on high ground, (d) if 

 deeply rooted, (e) if it is the best conductor. — A. D. W. 



Lime Sulphur as a Summer Spray. By C. Errett Wallace. 

 (U.S.A. Exp. Stn., Cornell; University of Nebraska Press, Bull. 37) — 



u 2 



