44 EXPERIMENT STATION RECORD. 



No. 3, pp. 639-658, fig. 1). — ^A number of cultural, fertilizer, and acclimatization 

 experiments with medicinal plants are reported. 



The degeneration of cultivated mints, B. Pateb {KisMet. Kozlem., 18 

 (1915), No. 3, pp. 625-638, pis. 5). — Experiments with a number of cultivated 

 mints showed more or less degeneration both in external and internal charac- 

 teristics. Among the more stable forms were the Hungarian spearmint, which is 

 apparently a variety of Mentha spicata generated vegetatively, and the Jap- 

 anese mint, which appears to be a true variety of M. arvensis. 



Commercial carnation cviltvire, edited by J. H. Dick {New York: A. T. 

 DeLaMare Printing & Publishing Co., Ltd., 1915, pp. 262, figs. 80). — A practical 

 guide to modern methods of growing the American carnation for market pur- 

 poses. Consideration is given to the following subjects : The carnation family ; 

 development of the carnation ; profits on carnations ; packing, shipping, and busi- 

 ness matters ; general cultural calendar ; sectional cultural treatises ; American 

 carnations in Europe ; the American carnation as an outdoor bedding plant ; the 

 Malmaison carnation ; border and annual carnations and pinks ; varieties of the 

 American carnation ; hybridizing and crossbreeding ; exhibiting and judging 

 carnations ; best tj-pe of greenhouse ; heating and fuel ; and insects, diseases, 

 and other pests. 



The cultivation of the perpetual flowering carnation, C. H. Taitdevin 

 (Cheltenham, England: Young <i Co., [1915], pp. 24). — A popular cultural 

 treatise with a monthly calendar of operations. 



Double seeding petunias, Myrtle S. Francis (Jour. Heredity, 6 (1915), 

 No. 10, pp. 456-461, figs. 3). — In this paper, read before the American Genetic 

 Association, at Berkeley, Cal., August 6, 1915, the author describes some crossing 

 and selection experiments in which four strains of double petunias that produced 

 seed have been secured from single and imperfect double types. 



Humidity, soil, and fertility studies with roses, M. A. Blake (Neic Jersey 

 Stas. Bui. 277 (1915), pp. 3-55, figs. 7). — This bulletin discusses the various 

 problems entering into tlie successful culture of greenhouse roses and describes 

 experiments conducted at the station with Killarney and American Beauty roses. 

 The experiments were started in May and June, 1912, and continued through the 

 1914 season. Special attention was given to the factor of humidity, since pre- 

 liminary experiments demonstrated that the failure of these varieties to make 

 proper growth during the winter months was due to the degree of humidity 

 rather than to either plant food, soil, water, or temperature factors. 



Observations upon humidity showed considerable variation in different parts 

 of the same greenhouse. Under usual greenhouse conditions humidity decreases 

 with increase of temperature and increases with decrease of temperature. The 

 character of the walks as well as the system of heating and ventilating directly 

 affected the humidity in the greenhouse. It was difficult to maintain a proper 

 degree of humiditj' in a greenhouse with cement walks, when it was necessary to 

 have all the heat circulating in the pipes. When cinders were placed over the 

 cement walks a higher degree of humidity was maintained. 



Lack of sufficient humidity caused American Beauty roses to be checked in 

 growth and the foliage to become hardened and fall from the stem. This re- 

 sulted in the death of many small roots in the soil. Plants also failed to de- 

 velop gi-owing shoots at the base when the humidity ranged from GO to 70 per 

 cent in winter. Under these conditions Pink Killarney was badly affected with 

 mildew, the flower buds were short, quite single in character, and lackeil sub- 

 stance. The sepals remainetl closed about the corolla and the flowers oi>ened 

 quickly on the plant and failed to keep well. When a humidity of 80 per cent 

 was maintained the growth of the roses and the quality of the flowers were 

 greatly improved. High humidity increased the size of the petals but tendetl to 



