486 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
All varieties of citrus grown in Florida have been affected, and all parts 
of the trees above-ground are susceptible to it. The bacteria are capable of 
growing in sterilized soil, and under favourable conditions may retain their 
vitality for long periods. They can withstand considerable drying or desiccation, 
which may be a factor in spreading the disease. 
It appears that high temperatures and high humidity favour a rapid develop- 
ment of the disease, and are largely responsible for its spread throughout Florida. 
A complete destruction of all infected trees is the only effective method 
known of checking the disease. — A . B. 
Citrus Fruits in the Gulf States, Handling and Shipping. By H. J. Ramsey 
(U.S.A. Dep. Agr., Farm. Bull. 696, Nov. 1915, 28 pp. ; 10 figs.). — Deals, inter 
alia, with the prevention of decay in transit, which is principally caused by 
blue mould, and, to a much smaller degree, by stem-end rot. — A. P. 
Citrus "Mottle-leaf." By L. J. Briggs, C. A. Jensen, and J. W. McLane 
(Jour. Agr. Res. vol. vi. No. 19, Aug. 1916, pp. 721-739 ; 3 plates, 4 figs.). — 
" Mottle-leaf " of Citrus trees is characterized by the disappearance of chloro- 
phyll from parts of the leaves, the portions farthest removed from the midrib 
and larger veins being first affected. These yellow spots increase in size until 
the chlorophyll is restricted to areas along the midrib and the larger veins. No 
organism has yet been proved to be causally associated with " mottle-leaf," 
but the Citrus root nematode is widely distributed in "mottled" districts. 
Soil analyses show a marked inverse correlation between the humus content 
and the mottling, the latter diminishing as the humus content increases, in 
the case of oranges. 
The humus content of the soils bearing lemon trees is less than that of the 
orange soils, and is apparently too low to produce a normal foliage growth, as 
the whole of the lemon groves were badly mottled. 
No relation was found between the percentage of leaves mottled and the 
total nitrogen content in the soil in either the orange groves or the lemon 
groves studied. 
The percentage of mottled leaves on orange trees is definitely correlated 
with the increase of the ratio of organic carbon to humus, indicating the im- 
portance of the organic matter in the soil being well decomposed. — A. B. 
Citrus Trees in Florida, Some Bark Diseases of. By J. G. Grossenbacher 
(Phytopathology , vi. pp. 29-50, Feb. 1916 ; figs.). — The symptoms and causes 
of the following diseases of Citrus trees are discussed fully : Gummosis, foot-rot 
or crown-rot, die-back, withertip, canker. — F. J. C. 
Clematis florida bicolor (C. Sieboldii). By S. Mottet (Rev. Hort. Sept. 16, 
1915). — One illustration, showing a fine specimen from Miss Willmott's garden. 
C. T. D. 
Clematis grata Hybrids. By Hortulus (Le Jard. vol. xxx. p. 45 ; 1 fig.).— The 
following hybrids were obtained from seed of Clematis grata : — ' Campanile ' 
forms a neat bush about five feet high, somewhat resembling C. Davidiana. 
The flowers are lilac-blue, with white centres. ' Cote d'Azur ' resembles C. 
tubulosa in foliage, and its flowers are deep azure-blue. ' Oiseau Bleu ' has slender 
foliage, with delicate panicles of lilac-blue flowers, changing to lilac-pink. — S. E. W. 
Clematis Pavoliniana (Bot. Mag. t. 8655). — China. Nat. Ord. Ranunculaceae, 
tribe Clematideae. Shrub. Leaves 3-foliolate. Leaflets 2-4 inches long. 
Flowers 3-umbellate. Sepals 4, green externally, white above, 2 inches across, 
from tip to tip. — G. H. 
Colletias. By N. E. Brown (Gard. Chron. Sept. 2, 9, and 16, 1916, pp. 108, 
121, and 131 ; 2 figs.).' — Reviews and rejects the evidence as to C. spinosa being 
the immature condition of cruciata, and declares the branches with slender spines, 
sometimes developed on cruciata, to be distinct in the flattened bases of the spines 
from those of true spinosa. 
The plant generally grown in gardens as spinosa is declared to be infausta, 
and here described. Descriptions are also given of armata Miers, and two new 
species, assimilis and trifurcata, — E. A, B. 
Colorado Potato Beetle, Life-history Studies of the. By Pauline M. Johnson 
and Anita M. Ballinger (Jour. Agr. Res. vol. v. No. 20, Feb. 1916, pp. 917- 
926 ; 1 plate).- — Details a series of observations upon the life -history of this 
destructive pest. It was found that the entire developmental period from egg 
