February 28, 1894.] 



Garden and Forest. 



81 



GARDEN AND FOREST. 



PUBLISHED WEEKLY BY 



THE GARDEN AND FOREST PUBLISHING CO. 



Office : Tribune Euilding, New York. 



Conducted by Professor C. S. Sargent. 



ENTERED AS SECOND-CLASS MATTER AT THE POST OFFICE AT NEW YORK, N. Y. 



NEW YORK, WEDNESDAY, FEBRUARY 28, 1894. 



TABLE OF CONTENTS. 



PAGE. 



Editorial Article: — Electricity and Plant-growing 81 



Notes for Mushroom-eaters. — VI. (With figures.). .Professor IV. G. Farlow. 82 



Exotic Trees and Shrubs tor Florida Gardens. — III H. Nekrling. S3 



Foreign Correspondence: — ParisLetter AIajtriceL.de Vihnorin. 83 



New or Little-known Plants : — Pyrus Miyabei. (With figure.) C. S. S. 84 



Cultural Department : — Eucharis Amazoriica IV. Scott. 86 



Flowering Plants for the Conservatory IV. H. Taphti. 86 



Hybrid Perpetual Roses for Forcing Plantsman. 86 



Annual Flowers from Seed. — III J. N. Gerard. 87 



Carnation William Scott E. O. Orfict. 87 



Wire Netting for Peas H. M. Btckwith. 87 



Solanum Seaforthianum T. 8S 



Correspondence : — Forest-land for Investment B. E. Fernaiv. 88 



The Longevity of Trees N. S. 88 



Notes from South Lancaster, Massachusetts IV. A r . Craig-. 88 



Recent Publications 89 



Notes 90 



Illustrations : — Scleroderma vulgare. Fig. 17 82 



Morchella esculenta. Fig. 18 82 



Pyrus Miyabei, Fig. 19 85 



Electricity and Plant-growing. 



FIFTY years ago experiments were made in Scotland to 

 test the influence of electric currents upon the growth 

 of plants, and since that time, both in Europe and America, 

 many attempts have been made to ascertain whether the 

 electrical condition of the soil or of the air had any influ- 

 ence upon vegetation, and how this influence, if it existed, 

 could be applied to practical advantage. We have pub- 

 lished at various times, within two or three years past, re- 

 ports of trials in which electric light had also been used for 

 the purpose of stimulating plant-growth. The latest sum- 

 mary of the results obtained in both these directions was 

 given at the last monthly meeting of the Massachusetts 

 Horticultural Society by Professor Bailey, and the subject 

 seems worth the attention of every one interested in horti- 

 cultural science. It should be added to what Professor 

 Bailey has stated that something like ten years ago agri- 

 cultural chemists were trying to ascertain whether plants 

 received any of their nitrogen directly from the air. It was 

 argued then that, under certain electrical conditions, free 

 nitrogen in some way combined with other substances, and 

 that the resulting compounds, dissolved by the soil-water, 

 were taken up by the feeding roots of vegetables. This 

 theory has not been disproved, but since "it has become 

 the accepted doctrine that there are living organisms which 

 attach themselves to the roots of plants, especially to the 

 roots of leguminous plants, and are able to secure a certain 

 quantity of nitrogen from the air for the use of such plants, 

 little investigation has been made to ascertain any possi- 

 ble connection betvveen electrical influence and the nitro- 

 gen supply of plants. Professor Bailey's remarks were 

 confined to the two subjects of illumination and direct 

 currents. 



In the first place, there seems to be no doubt that artifi- 

 cial light has the same kind of influence upon plants that 

 sunlight has, and that the influence is greater as the 

 light approaches the energy of solar light. Electric light 

 is used because it is the most powerful artificial light and 

 because it is similar to sunlight in quality, although rather 

 richer in the ultra violet rays, and, perhaps, rather weaker 

 in the orange rays. The use of an orange globe to make 

 an electric light resemble sunlight more closely seems to 

 give more rapidity of growth than when the light passes 



through glass of other colors. But this difference is so 

 slight as to be hardly appreciable. What seems to be de- 

 monstrated is, that electric light from a naked arc has 

 some injurious influence on plants growing within certain 

 distances, while they receive benefit when removed farther 

 away. Plants vary much as to their susceptibility to the 

 influence of this light. Under it Endive, Spinach, Cress 

 and Peas planted at Cornell University showed various re- 

 sults, while Carrots were almost invariably injured. Let- 

 tuce, on the contrary, was greatly benefited, particularly 

 when the light was burned only the first half of the night. 

 This result was confirmed by repeated tests, so that it can 

 be asserted that a 2,000-candle-power lamp, when it is run 

 half the night or less, has a marked influence for good 

 upon Lettuce in a house sixty feet square. 



The influence of naked light upon the productiveness of 

 flowers and upon their color varied in the tests made with 

 different species and with different colored flowers of the 

 same species. Several varieties of Tulips showed deeper 

 and richer colors when developed under the light, but 

 these colors lost their intensity in four or five days, and 

 were afterward not distinguishable from the colors of those 

 which were growing in unlighted houses. Under the light, 

 too, the plants had longer stems and larger leaves, and a 

 greater number of them were floriferous. Petunias grew 

 much taller and more slender when close under the light 

 than when twenty or thirty feet from the lamp, and they 

 bloomed earlier and more freely. White Petunias were not 

 changed in color by the light, but purple ones, especially 

 those nearest the lamp, quickly became blue. Other flowers 

 behaved differently, each according to its kind, but all 

 flowers, of whatever species, \vhich stood within five or 

 six feet of the naked arc were injured; they were of short 

 duration, while those which were twelve feet or more away 

 did not show any effect of this kind. What was generally 

 apparent was that the light hastened blooming, and flower- 

 ing plants grown in the light of an unscreened arc produced 

 longer stems. These good effects were counterbalanced 

 by some injuries, but it was subsequently found that the 

 use of a globe or a pane of glass would avert some of those 

 injuries to flowers as well as to foliage, while some increase 

 in earliness and strength was obtained. Nevertheless, it 

 must be said that we are not yet sufficiently acquainted 

 with the possible influence of electric light to advise its 

 adoption where flowers are grown. 



Since it seemed probable that the noxious effects of this 

 light could be overcome by the interposition of glass, the arc 

 surrounded by a globe was hung six feet above the middle 

 of a glass roof, and arrangements were made so that half the 

 house had no light while the other half received it. This 

 comparative test showed that Lettuce was greatly improved 

 in the light apartment ; Endive, which had been injured in 

 other experiments, showed no bad results, but no improve- 

 ment, while Radishes, which had been seriously injured be- 

 fore, showed a decided gain. It is worth observing that 

 when the light was modified by an opal globe the injury 

 was less serious, and that a light strained through a globe 

 and a glass roof gave an increase both to the tops and roots. 

 Similar results were obtained with Beets and Spinach, while 

 Cauliflowers were decidedly the best in a dark house; so 

 that while it is established that electric light can be profit- 

 ably used in the cultivation of Lettuce, and while it is prob- 

 able that flowers may be benefited, it is a fact that the dif- 

 ferent species and genera behave so differently that we 

 need much more experience before we can pronounce 

 definitely on any fact, except the one that the light does 

 exert a powerful influence. 



As to the direct effect of electric currents applied to 

 the plants, to the soil in which they grow or to the atmos-' 

 phere surrounding them, we as yet have no great amount 

 of accurate knowledge. We only know that at Amherst 

 College, in this country, and at several places in Europe, 

 wires have been stretched about fields and gardens and 

 charged with electricity. They have been passed through 

 the soil and similarly charged, and in the case of some 



