846 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



new localities respectively ; Sisyrinchium anceps in eleven new places. 

 This paper is No. viii. of the list, and would be much improved if a short 

 description of the exact meaning of the locality letters had been given. 

 There is no reference to the previous papers. — G. F. S.-E. 



Nicandra physaloides, Races of. By Georg Bitter (Beih. Bot. 

 Gent, xiv. pp. 145-176; with 6 plates). — Gives a description of the 

 varieties of this plant. Three characters are of importance : Colour of 

 stems, either (a) green or (b) violet ; honey guides (spots) on the petals. 

 Immaculate, maculated, integristellatce (star on petals). A third 

 character is the distance along the stem at which forking of the axis 

 begins. In " High-forkers " (Hochgabler) forking begins at 40 cm. to 

 180 cm. above the ground. " Medium-forkers " at from 20 to 40 cm. 

 " Low-forkers " (Tiefgabler) at from 7 to 25 cm. Of the possible 18 races 

 by combinations of these characters, the author has 8 in cultivation, and has 

 obtained 9 as hybrids which he hopes to establish. Another has been in 

 existence, but has died out. Possibly late-flowering varieties and others 

 with much divided leaves and laciniate sepals are also mentioned. A full 

 description is also given of the following other races. 



N. parvimaculata. Green, forking at 8-20 cm. with small conspicuous 

 dark-blue spots on the petals. Calyx 3 cm. in diameter, with hornlike 

 curved ends at the base. 



N. macrocalyx. Green, forking at 15-38 cm., small petal spots. 

 Leaf-blade distinctly limited, and not passing gradually into the stem. 

 Calyx in fruit about 3^ cm. long and 4 cm. wide, without marked 

 continuation points at the base. 



N. nebulosa. Green, forking at 26-55 cm., spots on petals misty pale 

 blue. White hairs on filaments. Calyx smaller than the last. Berries 

 at first violet-red, but becoming a pale green. 



N. nana. Green, forking at 3^-8 cm. ; calyx with sharp straight 

 points at base. 



N. brevicorollata. Violet, forking at 37-60 cm. Leaves often like 

 those of a Datura. Calyx in fruit 3-3^ cm. broad. Corolla short, 3 cm., 

 1 cm. longer than calyx. Star of five dark blue rays on petals. — G. F. S.-E. 



Nitrification, Notes on. By H. H. Cousins (Bull. Dep. Agr. Jam. 

 ii. pt. 1, p. 1). — The swiftness of decay and regeneration in the tropics 

 is attributed to nitrification. The most valuable commercial form of 

 nitrogenous fertilisers for use in a tropical country of free rainfall is 

 sulphate of ammonia. After giving a brief history of the discovery of 

 nitrification of ammonia by bacteria and a description of these organisms, 

 the following represents the changes undergone : — 



2NH 3 + 80 a + CaC0 3 = Ca(NO a ) 8 + C0 2 + 3H 2 0 



Ammonia + Oxygen + Chalk = Calcium Nitrite + Carbon dioxide + Water 



This change only goes on in the dark, and is independent of all organic 

 matter. To obtain C the organisms avail themselves of C0 2 . The 

 " nitroso " bacteria obtain their energy for the elimination of carbon from 

 the C0 2 by the supply they derive from the oxidation of ammonia to 

 nitrite. The amount of ammonia they are forced to oxidise in order to 



