NOTES AND ABSTRACTS. 
509 
sunken appearance on the tubers, which may show the pinkish-white growth of 
the fungus. The decayed tissue presents various colour shades, from nearly 
black to light brown . — F. J. C. 
Potentilla davurica var. Veitehii (Bot. Mag. t. 8637). — China. Nat. Ord. 
Rosaceae, tribe Potentilleae. Shrub, evergreen, 3-5 feet high. Leaves 1 inch 
long, 3-5 foliolate. Flowers solitary, white, 1 inch across. — G. H. 
Powdery Mildew in Roses (Qu. Agr. Jour. Nov. 1915, p. 298). — Boil 
1 lb. of flowers of sulphur and 1 lb. quicklime in 5 pints of water in an earthen- 
ware pot for ten minutes. Constantly stir while boiling ; then allow to settle, 
and pour off the clear liquid for use. The plants should be syringed with a 
mixture of this preparation diluted with a hundred times its bulk in water. 
C. H. H. 
Primula 'Asthore' (Irish Gard. xi. p. 117, Aug. 1916). — This is a hybrid 
between Primula Bulley ana and P. Beesiana, and seedlings from it raised in 1914, 
which have reverted to their ancestors, include orange, orange-red, pink, 
salmon, and various intermediate shades. — F. J. C. 
Primula x Edina. By S. Mottet (Rev. Hort. Jan. 16, 191 6). — Coloured plate 
showing three varieties, rich, orange to red, due to Cockburnia blood. Interesting 
notes in connexion with this and other hybrids. — C. T. D. 
Primula x kewensis, Genetic Behaviour of the Hybrid. By C. Pellew and F. M. 
Durham (Jour. Genetics, v. pp. 159-182 ; figs.). — When Primula verticillata and 
P. floribunda are crossed either way, plants resembling the seed parent are usually 
produced ; the offspring rarely segregate on being crossed, and generally breed 
true when selfed. Occasionally hybrids of the form of P. x kewensis are obtained 
as a result of the cross. These hybrids are of two kinds, one partially sterile, 
the other (with double the number of chromosomes) fertile. P. x kewensis selfed 
generally breeds true, except that it segregates into forms differing in degree of 
mealiness and in flower colour. Crossed with the parental types maternal hy- 
brids are produced with rare occurrences of segregation. A new type bred from 
P. kewensis x floribunda , however, did not breed true, but its seedlings approached 
P. floribunda. One of them on being selfed segregated, giving new forms between 
floribunda and verticillata, and varying considerably in shade between the pale 
Isabellina and the full yellow of floribunda type and kewensis. — F. J. C. 
Primulas, Notes on Some New. By Murray Hornibrook (Irish Gard. xii. 
Jan. 191 7, p. 8 ; 2 figs.). — The writer confesses that some of the new Primulas 
do not seem likely to prove " good garden plants," as they require a good deal 
of care, shade, and plenty of water. P. Veitehii is a hardy sort and showy. 
P. sinolisteri is like a small P. obconica. The writer then goes on to describe 
some of the sections of the newer Primulas — the section Muscarioides and Sol- 
danelloides ; the last section comprises some of the loveliest Primulas in existence. 
Concluding, he gives a few notes on the cultivation. — E. T. E. 
Productive and Less Productive Sections of a Field. By J. Lyttleton Lyon, 
J. A. Bizzell, and H. Joel Conn (U.S.A. Exp. Stn., Cornell, Bull. 338, Nov. 1913, 
pp. 49-116 ; 12 plates). — In a field on Cornell University farm two small tracts 
of land were noticed in 1905 which were so unproductive, with so little apparent 
cause for their infertility, that an investigation into this matter was begun by 
F. R. Reid and J. F. Breazeale. In the course of this work it was shown that 
soil from the unproductive area, when removed and placed in pots, produced 
better crops than from the soil of the productive areas in the field, and that this 
characteristic has remained constant up to the present time. 
Experiments by the first two authors of the present bulletin show that this 
greater productiveness of the poorer soil was largely due to the effect of aeration 
and caused a great increase in the formation of nitrates . It is therefore concluded 
that a too compact condition of the soil is the cause of the lessened productive- 
ness of certain sections of this soil for the growth of some crops. This is thought 
to be due to the adverse effect upon the formation of nitrates ; thus the qualities 
of productiveness, compactness, and rate of formation of nitrates are correlated. 
A bacteriological examination by H. Joel Conn showed that, except during 
the winter, the total number of bacteria was higher in the more compact and 
less productive sections of the field. The difference in total numbers lies wholly 
in the group known as ' slow growers.' Rapid liquefiers are often even fewer 
in the less productive than in the more productive sections. 
No type of bacteria found frequently in one soil was lacking in the other. A 
short bibliography is appended. — A . B. 
