248 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



as (1) ' Placoplasts," adjoining or immersed in the chromoplasts, and (2) 

 4 Libroplasts,* free along the median line.— M. H. 



Dichorisandra (?) Thysiana. By Ch. Pynaert {Rev. Eort. Beige, 

 xxv iii. No. ('». p. L88 ; col. pi.).— This was collected from the Congo. There 

 is a doubt as to its true generic name. The leaves are glossy and large. 

 It has not yet Howe red. — G. H. 



Diervilla Middendorffiana. By Sir J. D. Hooker (Bot. Mag. tab. 



7876). Nat. ord. Caprifoliacece, tribe Lonicerece. Native of Mongolia, 



Manchuria, and Japan. This is a glabrous shrub with black bark. Leaves 

 2-3 ins. broad. Cymes 3 ins. across, of pale yellow flowers, the lower 

 lobe speckled with orange. — G. H. 



Dipladenia. By Ad. Van den Heede (Be v. Hort. Beige, xxviii. No. G, 

 p. 130). — The author describes the genus, and gives details of culture and 

 habit.— G. H. 



Disa Kewensis ( ? g randiflora x i tripetaloides). By G. Borne- 



mann (Gartentlora, p. 57. plate 1510 ; 1/2 03). — A coloured plate and very 

 brief description of the hybrid.— J". P. 



Diseased Plants : Cases of Recovery under Cultivation. By 



P. llennings (Zcit. f. Pflanz. xiii. pp. 41-45; 1903). — Observations on 

 cases of plants attacked by rusts, smuts, and other parasitic fungi, which 

 have thrown oft* the disease. The plants were diseased when planted, but 

 after a few years' cultivation in the author's botanic garden became 

 healthy. — W. G. S. 



Dismal Swamp Region, Botanical Survey of the (U.S.A. Dep. 



Agr. t Div. of Botany, Cont. frcm Natl. Herb. vol. v. 6, xi. 1901; 13 plates, 

 14 figs., 2 maps). — The region surveyed was that part of South-east 

 Virginia and the adjacent portions of North Carolina which constitute the 

 district known as the Great Dismal Swamp. Two main objects were 

 kept in view during the investigation : (1) largely economic — " to ascertain 

 in what degree the character of the native vegetation of the region, varying 

 to a certain extent on different soils, may serve as an indication of the 

 quality and value of the soil " ; (2) purely scientific — to study the " ecological 

 distribution of the vegetation — in other words, of the various local assem- 

 blages in which the different species and forms are cambined to form the 

 plant cowring of the region as a whole." The climate is "as a whole 

 highly f a v< ii i a I h in all essential respects to the vigorous growth of . . . such 

 plant! M arc not especially equipped to endure any kind of extreme con- 

 ditions." There is a 1< ng growing period, a mild winter, abundant sunshine, 

 heavy and well distributed rainfall, and a high and remarkably uniform 

 percentage of atmospheric moisture. The physiography of the district 

 ifl next dealt with, then the soil. The maritime plant formations include 

 the salt-inarshes and sand-dune regions, while the inland include both 

 non hygrophile and fresh-water regions. The " associations " in the salt- 

 marsh formations are SparHna stricta association, at the immediate 

 <"l'-'e of the water ; ./ mens Romerianus, just within the Spartina belt ; the 



