NOTES AND ABSTRACTS. 
239 
No. 5, Oct. 1916, pp. 213-254; 1 fig., 11 plates). — The following summary 
of this work is given : — ■ 
1. Spongospora subterranea exists in six different potato -growing districts 
in the United States. 
2. Periods of damp, rainy, and cloudy weather favour the development 
of the fungus. Infection develops earlier on roots than on the tubers. 
3. The authors consider that cultural practices and soil water are important 
agents in spreading the disease. 
4. The fungus attacks seven other solanaceous hosts, including the tomato, 
besides the potato. The disease forms large galls on the roots of such hosts, and 
these galls have many points in common with the Plasmodiophora Brassiceae 
on the cabbage. 
5. The absence of the canker stage may be due to the short growing period 
afforded the potato crop in the infected districts of the United States. 
6. Amongst the saprophytic fungi found associated with 5. subterranea is a 
species of Papulospora, which may be easily confused with the first fungus because 
of similarity in shape of spore balls. 
7. There is a close relation between certain soil types and the development 
of the fungus. From the type of soil and its drainage, it is possible to predict 
what the development of the disease will be in any particular field. 
8. The dry-rot due to Phoma is the most serious of the rots. The species 
described is given the name of Phoma tuberosa, n. sp. 
A short bibliography is appended.— A. B, 
Potato, Tuber-Rot and Wilt of. A Physiological Study of Two Strains of 
Fusarium in their Causal Relation to Tuber Rot and Wilt of Potato. By George 
K. K. Link (Bot. Gaz. vol. lxii. Sept. 191 6 ; 13 figs.). — As the result of his 
investigations the author concludes : 
1. That both Fusarium oxysporum and F. trichothecioides (F. tuberivorum of 
Wilcox and Link) can produce both tuber rot and wilt of the potato plant. 
2. The wilt is induced by destruction of the root system and by clogging of 
the wood-vessels of the stem, and is, in mild cases, marked by such symptoms 
as discoloration of leaves, curling and rolling of leaves, and production of aerial 
tubers. 
3. Under field and storage conditions F. oxysporum is more probably 
responsible for wilt than is F. trichothecioides, and the latter more responsible 
for tuber rotting. 
4. The optimum and maximum temperatures of F. oxysporum are higher than 
those of F. trichothecioides. The former has a more rapid, superficial, and 
spreading habit of growth than the latter. 
5. Both organisms possess a striking ability to use the most diverse carbon 
material as carbon sources in their metabolism. — R. J. L. 
Potato, Weight of Seed per Acre. By J. T. Ramsay (Jour. Agr. Vict. Oct. 
1 91 7, p. 592). — For general practice the Department of Agriculture recommends 
27 inches between the rows, about 15 inches between the sets, with sets of an 
average weight of 2 oz. Approximately 17 cwt. of seed are required for an acre. 
Experience shows that fairlv heavy seeding and liberal manuring is sound business 
policy.— C. H. H. 
Potatos, Some Degenerate Strains of. By F. C. Stewart (U.S.A. Exp. Stn., 
New York, Bull. 422, July 1916, pp. 318-357; 12 plates). — The conclusions 
reached were that leaf -roll, curly-dwarf, and mosaic are closely related disorders, 
due to the same general undetermined cause. All are transmitted through the 
seed tubers, so that the progeny are similarly affected. 
There is no evidence that any of the above forms of degeneration are com- 
municable from one plant to another, except through the seed tubers. They 
are not due to any parasitic organism, nor can unfavourable soil or weather con- 
ditions be responsible. 
Neither normal foliage nor high yield is a guarantee of productivity in progeny 
the following season. Degeneration may occur quite suddenly. It is unsafe 
to select seed potatos from fields containing many degenerate plants. Even 
the normal plants from such fields may produce worthless progeny. It is 
doubtful if any method of seed selection will prevent the " running out " of 
seed potatos under certain conditions. — A. B, 
r Primula sinopurpurea. By B. (Irish Gard. xii. June 191 7, p. 88). — 
A "useful but brief description of a desirable new species. — E. T. E. 
