NOTES AND ABSTRACTS. 



393 



Club-root is prevented by use of lime. Disinfection of seed is useful in 

 preventing black -rot and black-leg. Drainage water and refuse from infected 

 plants is a fruitful cause of disease. — A. B. 



Cell Sap : Relation of Nutrient Solution to Composition and Reaction of 

 Cell Sap of Barley. By D. R. Hoagland (Bet. Gaz. vol. lxviii. No. 4, Oct. 1919, 

 pp. 297-304). — " The expressed sap from barley plants grown in water, sand, 

 and soil cultures under controlled conditions, has been examined, with the following 

 results : 



" i. The osmotic pressure in the sand and water cultures are reflected in 

 the cell sap of the tops and roots. 



"2. The electrical conductivity of the nutrient solution has a marked in- 

 fluence on the conductivity of the sap. This is as marked for the tops as for 

 the roots. The conductivity of the plant sap is from four to fifty times greater 

 than that of the nutrient solution. 



"3. The sap from the tops of all plants grown in sand and soil cultures, or 

 water cultures of different concentrations and reactions had almost the same 

 Ph value, approximately 6*o. 



" 4. Samples of sap from plants grown on six different soils under the same 

 climatic conditions were analysed for important elements. In every case the 

 concentration in the sap was found to be very much greater than in the soil 

 solution. 



"5. The dynamic nature of the relation between the soil solution and the 

 plant is emphasized." — R. J. L. 



Cherry Leaf Spot Disease Control. By J. W. Roberts and L. Pierce (U.S.A. 

 Dep. Agr., Farm. Bull. 1053 ; 7 pp.). — The leaf spot of the cherry injures both 

 sweet and sour varieties of this fruit in many of the Eastern States. The disease 

 is caused by a fungus which attacks the leaves, causing them to become " shot- 

 holed." The fungus reproduces by ascospores and conidia. 



The best control measure is by spraying with a diluted lime-sulphur solution 

 or with Bordeaux mixture when the petals fall, when the fruit is maturing, and 

 when the fruit has been picked. — A. B. 



Chinese Plants, New. Arbores Fruticesqae Chinenses Novi III. By Camillo 

 Schneider (Bot. Gaz. vol. lxiv. No. i, July 191 7 ; pp. 70-78). — The author 

 describes the following new species and varieties : 



(1) Cotoneaster (sect. Chaenopetalum Koeh.) oligocarpa, n. sp. 



(2) C. (sect. Chaenopetalum Koeh.) Vernae, n. sp. 



(3) Prunus latidentata Koeh., var. trichostoma, n. var. 



(4) Potentilla eriocarpa Wall., var. cathayana, n. var. 



(5) Rubus (sub-gen. Idaeobatus Focke, sect. Idaeanthi Focke) testaceus, n. sp. 



(6) Rosa Mairei Lev., var. plurijuga, n. var. 



(7) Rosa (sect. Cinnamomeae D.C.) atroglandulosa, n. sp. 



(8) Rosa Soulieana Crep., var. yunnanensis, var. nov. 



(9) Viburnum cylindricum Ham., var. crassifolium, n. var. 



(10) V. calvum Rehd., var. puberulum, n. var. R. J. L. 



Chinese Plants, New. Arbores Fruticesque Chinenses Novi, IV. By Camillo 

 Schneider (Bot. Gaz. vol. lxiv. No. 2, Aug. 191 7 ; pp. 137-148 ; with 1 plate). — 

 Eight new species of Salix are described and one of Alnus, viz.: 



(1) Salix (sect. Sclerophyllae Schn.) tenella. 



(2) S. (sect. Eriostachyae Schn.) Balfouriana. 



(3) S. (sect. Psilostigmatae Schn.) Guebriantiana. 



(4) S. (sect. Psilostigmatae Schn.) wolohoensis. 



(5) S. (prob. sect. Denticulatae Schn.) caloneura. 



(6) S. (prob. sect. Phylicifoliae Dum.) squarrosa. 



(7) S. (sect. Diplodictyae Schn.) Faxoniana. 



(8) S. (? sect. Sieboldianae Seem.) dibapha. 



(9) Alnus (sub-genus Cremastogyne [Winkl.] Schn.). R. J. L. 



Chrysanthemum, " Crack neck," a non-parasitic disease of. By G. H. 



Chapman [Phytopathology, 9, p. 532 ; Nov. 1919; figs.). — The stem cracks trans- 

 versely just below the flower head in the bud stage. This is said to be due to 

 turgor arising from continued root activity with a lowered temperature about 

 the stems. Care in watering during dull weather and the maintenance of a 

 reasonable night temperature are regarded as the best means of avoiding the 

 trouble. — F. J. C. 



