NOTES AND ABSTRACTS. 
56l 
August, finally becoming almost black. The older spots are limited by the veins. 
On the conns the spots are at first minute, usually on the lower, but sometimes 
also on the upper part of the corm, and seen only after removing the tunics. 
Later the centre of the spot becomes sunken, the tissue black, and the margin 
more definite. There is a distinct hardening of the tissues, so that they are 
difficult to cut with a knife. Plants grown from diseased cormsare more or less 
stunted, often fail to flower, and quickly lose their leaves, which turn brown and 
die. The author found the fungus Septoria Gladioli Passer always associated 
with the disease, carried out inoculation experiments, and gives drawings of 
fungus and diseased tissues. Crop rotation, the planting of healtHy cormsonly, 
and the destruction of diseased foliage and corms are the measures recommended. 
i% /. C. 
Hop Resistant to Mildew, On Forms of the. By E. S, Salmon {Jour. Agr. 
Sci. vol. viii. part 4, Dec. 191 7, pp. 455-460), — The author has observed 
that two seedling hop p.ants raised from seed ot the wild Humulus Lupulus 
procured from Italy were not attacked by Mildew {Spaerolheca Humuli) when 
exposed with several hundred one- and two-year-old seedling hops under con- 
ditions extremely favourable to Mildew. All the other seedlings were infected. 
Subsequently a similar immunity was observed in the case of seven out of about 
one hundred and sixty seedlings, also raised from Italian seed of the wild plants 
and grown under conditions very favourable to Mildew. Humulus Lupulus 
in the wild state therefore comprises forms which may be either very susceptible 
or very resistant to attack by 5. Humuli. Whether these forms are morpho- 
logically identical or not has not yet been determined. It may be that they 
are " biologic forms," such as have been observed among plants of Spiraea 
Ulmaria, Epilobium monlanum, Ranunculus repens, Sec. — /. E. W. E< H. 
Huntl8ya citrina Rolfe {Bot. Mag. t. 8689 ; Dec. 1916). — Orchidaceae (Vandeae). 
A plant from the collection of the late Sir Trevor Lawrence, native of Colombia. 
An epiphytic species with numerous pale-green distichous leaves 6 to 11 inches 
long. The solitary flowers are axillary, pale yellow, with a blood-red crest to the 
lip, and borne on pedicels about 2 inches long. — F f J, C, 
Insect Metabolism, the Influence of Atmospheric Humidity on, Some Facts 
relative to. By Ihos. J. Headlee, Ph.D. {Jour. Econ. Entom. x., pp. 31-38; 
Feb. 1917). — The author opens his paper by stating some known cases of the 
influence of atmospheric humidity on various stages of insect development ; 
and goes on to give a detailed account of some experiments carried out with the 
bean weevil {Bruchus obtectus Say.), and the Angoumois grain moth {Sitotroga 
cerealella Oliv.). It is shown that air in which the humidity is kept low by 
H 2 S0 4 may be so dry as to prevent the bean weevil from carrying out its life 
history or even entering the seed. A reference is given to a native method in 
Rhodesia of protecting maize from weevils by mixing it with finely powdered 
wood ashes, and it is also noted that a layer of wood ashes on the outside of the 
sack alone is effective. A layer of building lime on the floor of the storing place 
and between successive layers of bags gives satisfactory results ; and it is sug- 
gested that whilst one would naturally attribute the results to the caustic effect 
of the ashes or lime, the fact that protection is secured, even when the substances 
are not in direct contact with the seed, may be due to the well-known hygroscopic 
properties of ashes and lime. The author suspects that here we have the practical 
application of the effect of low relative humidity. — G. W. G. 
Insecticide, Quassia Extract as a Contact. By N. E. Mclndoo and A. F. 
Sievers {Jour. Agr. Res. x. pp. 497-531 ; Sept. 1917). — A long paper detailing 
a arge number of experiments and cone uding that in general quassia extracts 
are not efficient insectic des, although solutions may be made which are effective 
against certain species of aphis. — F. J. C. 
Irises of June, The Garden. By G. Dillistone {Gard. July 21, 1917, p. 
286). — This article contains a useful review of Garden Irises flowering in June, 
particularly of some of the new varieties. — H. R. D. 
Juniperus Cedrus. By G. V. Perez {Jour. Soc. Nat. d'Hort. France, Jan. 
J 9i 7)- — An account of the cultivation of this rare native of the Canaries. — F. J. C, 
Kelp, Potash from. By K. Cameron {U.S.A. Dep. Agr., Bur. of Soils, Bull. 
100 ; 40 plates, 33 tables). — A comprehensive description of the kelp beds of 
the United States, the method of harvesting from same, and the preparation of 
potash salts witn the residue of valuable by-products. 
