482 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Muehlenbeekia complexa (Bot. Mag. tab. 8449).— New Zealand. 



Family Polygonaceae, tribe Coccolobeae. Herb, with thin, woody, 

 slender stems forming dense tufted masses, or climbing over shrubs, 

 &c. Inflorescence, short spikes ; perianth white, 2 lines long. — G. H. 



Nitrification, Influence of certain Soil Constituents upon. By 



John W. Paterson (Jour. Dep. Agr. Vict. July 1912, pp. 393-400). 

 — (1) Mild lime is an effective means of promoting nitrification, and 

 its action begins at once. (2) It is a safe dressing both as regards 

 quantity and time of application. (3) Caustic lime requires greater 

 caution in its use. (4) It should not be applied too near the time of 

 seeding. (5) It should not be applied during the growth of any crop. 

 (6) It should be used in smaller quantities than mild lime. (7) It will 

 probably have a similar action to mild lime eventually. (8) Magnesiun 

 carbonate in a limestone may or may not damage crops, but it appears 

 to favour nitrification. (9) Red and brown soils, other things being 

 equal, favour nitrification, as they contain a slow-acting base in the 

 form of iron rust. (10) Gypsum is a slow form in which to apply 

 lime. (11) Superphosphate may prove a useful aid to nitrification on 

 some soils. (12) Salt delays nitrification. (13) Sour soils are very 

 unfavourable to nitrification. (14) Ploughing in of green or fresh 

 stable manure may cause a temporary shortage of nitrates, particu- 

 larly on damp soil. (15) The nitrifying organisms are weakened by 

 continued drought, and where the surface soil becomes unduly parched 

 in a dry spell nitrification will begin slowly after rain comes. — C. H. H. 



Nymphaeas <Mme. Paul Cazeneuve ' and 'Mme. Abel Chatenay.' 



By G. T. Grignan (Rev. Hort. Feb. 16, 1913 ; p. 84 ; coloured plate). 

 — Two very beautiful Water-lilies. The first-named double, white, 

 suffused with rose, the second also double, of a delicate pale blue, 

 central stamens bright yellow, with blue recurved tops. Under- 

 surface of leaves veined pink. — C. T. D. 



Olive Knot Disease, Method of Spreading. By W. I. Home, 



W. B. Parker, and L. L. Daines (Phytopathology, ii. p. 101 ; June 1912). 

 — Olive knot disease is caused by Bacillus Savastanoi (Journal R.H.S. 

 xxxiv. p. 586). The authors consider that the bacilli are distributed 

 by rain spattering the moist exudations which proceed from the 

 knots and which contain living bacilli. These find their way into 

 minute cracks and set up the disease. — F. J. C. 



Oncidium pulchellum, Hook. By E. Miethe (Orchis, vol. vi. 

 pt. viii. pp. 149-151 ; 1 fig.). — The orchid described by Heydt in 

 Orchis, pt. iv. vol. vi., is not 0. pulchellum, as is seen from the 

 illustration accompanying this article. — 5. E. W. 



Oranges, Sooty Mould or Fumagine on (Agr. Gaz. N.S.W. 

 p. 989). — Sooty mould on oranges is caused by the fungus Capnodium 

 cilricolum, which attacks the leaves, branches, and fruit. Prune off 

 and burn the diseased branches, spray with resin wash or fumigate 

 with hydrocyanic acid for 40 minutes. — S. E, W. 



