156 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Oenothera, Mutants of. By F. M. Andrews (Bot. Gaz. pp. 

 193-201, Sept. 1910). — Describes the characters of Oenothera 

 Lamarckiana, 0. biennis, 0. laeta, and 0. velutina. The European 

 0. biennis differs from the American type of the same plant. The 

 so-called twin hybrids " laeta and velutina are distinct, and so far 

 as yet investigated constant forms. 



Their anther cells do not open on rainy days and seldom on sunny 

 days.— G. F. S. E. 



Oranges, Stock fov{Rev. Hort. de VAlgSrie, p. 67, March 1911). 

 There are two distinct types of orange stocks in Algeria, known as 

 * Citron Galeux ' and ' Citrus de Floride. ' One of these has violet- 

 tinted flowers, and is more or less related to the lemon; the other is 

 the real "rough-lemon," with white flowers, which derives from the 

 lime. This last is the only variety which sufficiently resists disease, 

 ^ind in general no stock of which the buds or flowers are tinted with 

 violet should ever be used. — M. L. H. 



Orchard Insects, Information about Spraying" for. By A. L. 



Quaintance (U.S.A. Dep. Agr., Year Book, 1908; 5 plates). — Princi- 

 pally a description of spraying outfits and apparatus, with formulae of 

 approved spraying solutions. — V. G. J. 



Orchards, Irrigation of. By S. Fortier (U.S.A. Dep. Agr., 

 Farmers' Bull. 404- , June 1910; 32 figs.). — The practical side of the 

 subject is dealt with very fully. It is held that examinations of the 

 tree itself are not sufficient as a guide to the best time to irrigate, but 

 that it should be found out where the bulk of the feeding roots are 

 located, and frequent tests made as to the moisture of the surrounding 

 soil (p. 24).— A. P. 



Orchards, Vegetable Pests in (Gartenflora, vol. Ix. pt. xix. 



pp. 429-36). — Toothwort (Lathraea squamaria) attacks the roots of 

 apple and pear trees, doing much damage. On no account should 

 mistletoe be permitted to grow in orchards. 



To protect trees from the attacks of the larger fungi, paint wounds 

 on the stems and branches with tar and burn all diseased and decayed 

 wood. Unprotected wounds give admission to the spores of Polyporus 

 caudicinus, which does much damage to pear, plum, cherry, and nut 

 trees. P. squamosus, recognized by its odour of fennel, attacks nut and 

 pear trees. Phaeoporus Jiispidus confines its ravages to apple trees. 

 Ochroporus igniarius is one of the commonest and most dangerous fungi 

 in the orchard. Trees attacked by this parasite must be burned. The 

 most dangerous of all is Armillaria mellea. This edible fungus is a 

 parasite and a saprophyte. It attacks the tree at the junction of the 

 root and the stem, penetrating the bark and destroying the woody fibre 

 of the stem. 



Pholiota squarrosa preys on apple, cherry, and nut trees; Agaricus 

 galericulatus destroys apple and cherry trees; and Hydnum Schieder- 

 mayeri confines its ravages to the apple. 



