$8o JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY, 
flowers deemed suitable for war-time. We notice that one of the best of all 
war-time flowers {Calendula grandifiora ' Prince of Orange ' ) is omitted. 
E. T. E. 
Wasp Enticer. By Pennick Jones (Gard. June 16, 191 7, p. 220). — Pyrut 
erythrocarpus in bloom in June exercises a peculiar fascination to queen wasps, 
and the author states he had captured many scores on a bed of these plants, and 
it should be tried in every garden for this purpose. The plant is also very 
attractive, with its glossy leafage and striking autumnal tints. The showy 
black sheeny berries borne till winter enhance its merits. — H. R. D. 
Water-lilies, Leaf-spot of. By F. V. Rand (Jour. Agr.Res. viii. pp. 219-232, 
February 191 7; figs.). — The disease appears first as tiny black specks on the leaf 
blade, often reddish or bordered with red. Later the entire leaf may become a 
dark greenish black mass of tissue that falls apart on the slightest touch. The 
causal fungus was isolated from the leaves of Nymphaea olorata and proves to 
be a new species, which is named Hclicosporium nymphaearum. — J% /. C. 
Water-Melon Diseases. By W. A. Orton (U.S.A. Dep. Agr., Farm. Bull. 821, 
May 1917; 11 figs.). — This bulletin gives a popular account of the comironer 
diseases of the water-melon, including " Wilt," caused by Fusarium niveum 
Erw. Sm.; "Root-knot," caused by nematode Heterodera radicicola (Greef) 
Miiller; Anthracnose, caused by Colletotrichum lagenarium (Pass.) Ell. and Halst. 3 
Stem End Rot, caused by Diplodia sp. ; Stem Blight, caused by Mycosphaerella 
citrullina (Sm.)Gr. ; Bacterial Wilt, caused by Bacillus tracheiphilus (Erw. Sm.); 
and Downy Mildew, caused by Peronoplasmopara cubensis (B. and C.) Clint, 
Control measures are suggested for the various diseases. — A. B. 
Watering at Midday. By C. Riviere (Rev. Hort. vol. xc. pp. 86-87). — Ex- 
periments show that when cultivated soil exposed to the sun at midday is watered, 
only a fall of 6° F. is observed at a depth of 4 inches. This is not sufficient to 
check the growth of a plant. The effect is much greater in an unfilled soil, 
or in pots. When a plant flags, water it whatever the temperature may be, 
5, E, W a 
Water in a Soil, Relation of Movement to Hygroscopicity and Initial Moistness. 
By F, J. Alway and G, R. McDole (Jour. Agr. Res. x. pp. 391-428; Aug. 
1917). — The downward movement of water and rate of penetration under various 
conditions of moisture and composition are dealt with. Comparisons are made 
with the rate and height of capillary rise, and they are found not to coincide 
withrate and depth of penetration in the same soil. — F. J s C.» 
Weeds, Effect on Crops. By Dr. Winifred Brenchley (Jour. Bd\ Agr. vol. xxix. 
No. 12 March 1918). — Gives results of some experiments undertaken at 
Rothamstead to test the amount of harm wrought by weeds on crops. The 
conclusion came to was that " the essential factor in the relation of crop with 
weed is that of competition for food, space, and light rather than that of the 
toxic excreta from roots." There was no evidence of any poisonous secretion 
from the roots, although other investigators have reached different conclusions. 
In connexion with the competition for food, space, and light, it was proved that 
thickly sown wheat made less growth, plant for plant, than thinly sown wheat 
in the presence of weed, indicating that the competitive action of wheat with 
itself was stronger than that of the weeds. — G. C G. 
Weeds : How to Control them. By H. R. Cox (U.S.A. Dep. Agr., Farm. 
Bull. 660, May 12, 1915 ; pi.). — Three injunctions are laid upon the farmer 
which will remove the need for much of this work of weed destruction by re- 
moving the cause of weed growth ; — 
(1) Prevent weeds from going to seed, 
(2) Prevent weed seed from being brought to the farm, 
(3) Frevent perennial weeds from making top growth, and so starve out the 
underground parts. 
This bulletin is divided into sections dealing with each of these stages in the 
extinction of weeds, and gives a list of the fifty worst weeds in the United States, 
with their characters, duration of life, a short description of each, and where and 
under what conditions they do most mischief. — M. L. H. 
■ Weeds of New South Wales. By J, H, Maiden (Agr. Gax. N.S.W, vol. xxviii, 
PP* 409-416 and 563-570 ; xxix, pp. 31-37 J 5 plates), — Blue Weed (Echiunt 
