NOTES AND ABSTRACTS. 



819 



Japanese spindle trees were attacked by Oidium Euonymi japonicae. 

 The cause of the black spot on ivy leaves has not yet been ascertained. 

 The caterpillars of Gracilaria syringella have done much damage. 



S. E. W. 



Plant Food Removed by Rain op Dew. By J. A. Le Clerc and 



J. F. Breareale (U.S.A. Dep. Agr. Year Book, 1908; pp. 7).— 

 Contains resume of work by Wehmer, Willfarth, Eomer, Wimmer, &c., 

 and some original work. The main point brought forward is that plants 

 exude salts on their surfaces, and therefore ash analyses are misleading, 

 as these exuded salts are washed by rain and dew back to the soil. 



E. A. Bd. 



Plants, The Sleep of. By Paul Noel (Jo?/r. Soc. Nat. Hort. Fr. 

 ser. iv. vol. xi. p. 98; Jan. 1910). — A method of retarding the flower- 

 ing season of fruit trees which are liable to suffer from late frosts is 

 here described. On March 27 a hole was made with a stick just by the 

 roots of each tree. The hole should be the size of the stick, and 

 38 to 40 centimetres deep. Into this hole 200 cubic centimetres of 

 ether, or better still of chloroform, was poured, and the hole was closed 

 up with a sod. If necessary the operation should be renewed about 

 April 15. It was thought at first that the retarding was due to the 

 action of the ether on the tree itself, and the experiment was tried of 

 inoculating the trunk with the anaesthetic or administering it to the 

 tree in some other way. As none of these plans produced any effect, 

 however, it was clear that the retarding of growth was due to the 

 chilling of the ground through the rapid evaporation of the ether. 



M. L. H. 



Platycerium, Two Species of. By Dr. H. Christ (Ann. Jard. 

 Bot. Buit. 3rd supp. 1st part, 1910, pp. 7-12; with 2 plates).— This 

 paper deals with two species of Platyceriu7n—n?ime\y, P. sumhawense 

 (Christ) and P. Ridleyi (nov. spec). 



In 1908 Eidley described a Platycerium from the Malay Peninsula 

 under the name of P. bijorme var. erecta, and at about the same 

 trrne Alderwerelt described a fern discovered by himself in the Lingga 

 Islands under the name of P. coronarium var. cucullatum. These appear 

 to be one and the same thing, and in the present paper Christ gives, a 

 photograph and full description of the plant under the title of P. 

 Ridleyi. 



The curious slipper-shaped and hooded fertile-frond is described, 

 and it is pointed out that this affords protection to the sporangia both 

 against excessive desiccation and also against the dangers which would 

 ensue from the heavy torrential rains. — R. B. 



Plum Pests. By A. L. Clement (Jour. Soc. Nat. Hort. Fr. ser. iv. 

 vol. xi. p. 221 ; April 1910). — Several insects very harmful to plum 

 trees are described and their life-history given.. These are Hoplocampa 

 fnlvicornis and H. crataegi, Grapholita funebrana, Yponomeuta padella 

 and Tortrix or Penthina pruniana. Shaking the tree over a cloth during 



3 H 2 



