705 



THE GARDENERS' CHRONICLE. 



had started up some day at the touch of an enchanter's 

 wand." 



Cyclamen cilicium of Boissier also grows here in 

 plenty, and a good store of roots is announced as 

 having been collected. This is a charming little 

 Alpine plant, with flowers resembling those of 

 Coum, but not much bigger than Violets. Its leaves 

 are at present unknown. 



M. Balansa in conclusion announces that he is 

 about to start for the village of Galet-Boghaz, the 

 summer residence of the merchants of Tarsus and 

 Adana, where he expects a rich harvest of Alpine 

 plants. We heartily wish him good speed. 



In the last number of the Edinburgh New- Phi- 

 losophical Journal, a scientific periodical conducted 

 with great ability, there is a very interesting paper 

 by Professor Goodsir, on the present state of our 

 knowledge of the Electrical Phenomena observ- 

 able in Plants. A subject of this kind is too 

 remote from practical application, as far as has 

 yet been ascertained, to be allowed much space in 

 our columns ; nevertheless it is so curious that we 

 venture to draw up from Mr. Goodsir's narrative 

 a slight sketch of what has been hitherto done, 

 which will we doubt not prove interesting to many 

 of our readers. It is now, we believe, more than 

 20 years since Donne, a skilful French experi- 

 mentalist, directed his attention to the water plants 

 called CharadSy the movements observable in 

 which had been supposed to be caused by electrical 

 action. Dutrochet and Becquerel examined the 

 same phenomena, and from time to time a variety 

 of other desultory inquiries have been prosecuted. 

 Among others our countryman, Mr. Thwaites, now 

 in charge of the Government Botanic Garden in 

 Ceylon, satisfied himself that the very fabric of a 

 plant, its cells, and tubes, and vessels, was due to 

 the action 

 matter. 



The facts collected by Mr. Goodsir present some- 

 thing more tangible than speculation. For although, 

 as he remarks, the researches themselves are not yet 

 sufficiently advanced to admit of a satisfactory 

 analysis, and electrical effects are so complex that 

 it is unsafe to draw any conclusion regarding the 

 part which electricity takes in the organic functions, 



distance above the other, or if one be inserted 

 between the bark and wood, and the other be passed 

 through a number of leaves, superimposed and still 

 adherent, the needle will indicate a current passing 

 from below upwards through the parenchyma, the 

 upper electrode indicating positive, the lower 

 negative electricity. The same observer also finds 

 a descending current passing from the stem through 

 the roots into the earth, which therefore becomes 



Wartmann states that 



[Oct. 27, 1855 



from currents 

 are produced by the insertion of the electrode*? 

 M. Becquerel expresses himself very cautiouslv on 

 this point. He, however, admits that the "tw* 

 necessary conditions for the production of primary 

 currents exist in the plant. The first is, that two 



positive around the plant, 

 in the roots, the stem, the branches, the petioles, 

 and peduncles, there exist a central descending 

 current, and a peripheral ascending one, which he 

 denominates axial currents; and that the galvano- 

 meter indicates currents from every part of the 

 plant, aerial or subterranean, to the soil, which is 

 thus positive in relation to the plant. 



A variety of experiments show that electrical 

 currents pass from within outicards, and from with- 

 out inicards in the horizontal section of Dicotyledons. 

 According to Becquerel, if one electrode be in- 

 serted into the pith of a young Poplar and the other 

 into one of the woody layers, or into the bark, a 

 current from without inwards is indicated, the elec- 

 trode in the pith being positive, that in the wood or 

 bark negative. On removing a piece of bark, and 

 applying the electrodes to its opposite surfaces, the 

 current becomes very intense. The piece of bark 

 thus forms a voltaic couple, of which the exterior is 

 positive, and the interior, covered by cambium, 



then that from the pith to the 



of electrical currents among mucous 



negative. 



It would appe 

 cambium the woody layers are less and less positive 

 in relation to the pith ; whilst from the cambium to 

 the cuticle, the parenchymatous layers are more 

 positive, or at least comport themselves as such in 

 the production of derived currents. This inversion 

 of the electrical effects corresponds with the relative 

 position of the cellular texture in the bark and wood. 

 In the bark it is on the exterior ; in the wood, in the 

 interior ; in both it is positive. 



liquids capable of acting chemically on one another 

 should be arranged so as to do so gradually an 

 continuously. The other is the intervention of a 

 conducting substance to complete the circuit. Upon, 

 the whole this observer seems inclined to admit the 

 two axial currents, and the horizontal system in the 

 stem and branches of dicotyledons. 



Wartmann admits that the tearing of the tissues 

 during the insertion of the electrodes produces at 

 first a considerable deflection of the needle, but adds, 

 that this action speedily ceases, when there remains 

 a more feeble current, which must be due to the 

 normal electrical action of the parts. He thinks 

 that vegetable currents probably form closed circuits; 

 that the extremities of the root fibres on the one 

 hand, and the terminations of the leaves on the 

 other, establish a continuity between the ascending 

 peripheral and descending central current; while 

 the similarity in the electrical condition of the 

 exterior of the bark and the interior of the wood 

 probably depends on the medullary rays. 



As a general conclusion to be drawn from such 

 facts as have been now described, Mr. Goodsir 

 thinks it can only be stated generally that the dis- 

 turbance of electric equilibrium in the textures and 

 organs of the plant is due to the chemical action 

 which plays so important a part in the organic pro- 

 j cesses — at its surface, as during transpiration, 

 respiration proper, and the fixation of carbon — and 

 in its interior, during the reaction of its ascending 

 and descending sap, with the substances contained 

 in the cells of its various structures. No precise 

 statement can be made at present regarding the 

 arrangements by means of which electrical currents 

 are produced in the plant. The researches of 



f — - — — — — — — f— — - ■ — -— — » — — » -■" - ■»■ w ™» ^-» v- »*- w — ^r — «*- ■»- »- 



Wartmann states that " in uniting by the gal vano- Becquerel have proved indeed that a current is 



>ter the layers of the stem where the liber and produced when two liquids of acid and alkaline re- 



J .1 f -\ t . • .** « m m . m 



me 



cambium touch 



one another (and where many 



botanists admit a passage of descending j 

 either with the most central parts (the pith or the 



actions respectively, and separated from one another 

 by a porous substance, are connected either by a 

 fluid or solid conductor, and it is evident that 



, , . - - / , perfect wood), or with the parts more exterior (the similar physical and chemical conditions exist in 



nevertheless certain facts have now been positively young bark), a lateral current will be found tending innumerable forms in the organisation of vegetables. 



It is, however, impossible in the present phase or 



ascertained, although there remains much difficulty 

 in determining whether certain currents, indicated 

 by the instrument, are primary or derived ; and also 

 in ascertaining how far the observed currents are 

 produced by unavoidable injury of texture, and 

 consequent mixture of fluids. 



The general arrangement of the parts of a plant, 

 and the functions they perform, indicate the pro- 

 bable direction of the resulting electrical distur- 

 bances. The differences in the constitution of the 

 ascending and descending portions of the axis, and 

 of their transverse segments, naturally indicate the 

 existence of longitudinal currents ; while the struc- 

 tural and functional differences between the central 

 and superficial portions of the axis point to trans- 

 verse or radiating lines of force. Accordingly, all 

 observations indicate currents in the longitudinal 

 and transverse direction, in roots, tubers, stems, 

 leaves, flowers, and fruits. 



In considering the electrical reactions of the plant, 

 soil, and atmosphere, it is found that the soil is in a 

 constant negative, while the air when calm and free 

 from clouds is in a positive electric condition. 



According to Pouillet, plants in the later stages 

 of germination, after they have protruded from the 

 soil, exhibit by the condenser an excess of negative 

 electricity. The explanation he gives is that the 

 action of the oxygen of the air on the starch of the 

 seed, during its conversion, gives an excess of 



NEW GARDEN FERNS.— No. VI. 



15. Lastrea recedens, J. Smith, MS. Polypodia 

 receoens, J. Sm., En. Fil. Phil., Hook. Journ. 

 Bot. iii. 394. Lastrea elegans, of gardens. 



Frouds pentangular, densely pubescent, glandulose, tripinnate • 

 pinnules linear-oblong, acute, decurrent, deeply pinnatifid, 

 with short dentate segments; sori submarginal; stipes ad- 

 herent to a creeping rhizome. 



This very elegant Fern is a native of Ceylon and the 

 Philippine Isles; the cultivated plant was sent from the 

 former place, by the late Dr. Gardner, to Kew. Its- 

 fronds which have a longish stipes, scaly at the base, 

 grow a foot and a half or two feet high, and are of a light 

 green colour, densely covered with short hairs inter- 

 mixed with glands. The outline is pentangular, the two 



positive electricity to the air, and of negative elec- 

 tricity to the plant and soil. 



But according to M. Becquerel the electrical 

 relations of the plant to the soil and air are reversed 

 after germination is completed. If the electrodes of 

 the galvanometer are inserted, the one into the stem 

 or branch, or passed through a number of leaves laid 

 together, but still adherent — the other into the soil 



the former will exhibit an excess of negative, thp 



latter of positive electricity, in proportion to the 

 humidity of the soil and the succulence of the plant. 



from these layers to the neighbouring organs." 



It would appear, therefore, that currents pass the subject to define them with greater precision, 

 from the contiguous surfaces of the bark and wood 

 of the dicotyledonous plant outwards towards the 

 cuticle, and inwards to the pith. 



As to currents in leaves the observations of both 

 Becquerel and Wartmann lead to the conclusion 

 that currents set from the cambium to the paren- 

 chyma of the leaf; while at the same time it is 

 negative in relation to the pith and wood of the 

 branch and stem, the leaves behaving as the green 

 part of the parenchyma of the bark ; that is to say, 

 the sap which circulates in their tissues is negative 

 in relation to the wood, pith, and soil, and positive 

 in relation to the cambium. 



This centripetal current is referable to the central 

 or descending axial current of the plant; while the 

 centrifugal belongs to the superficial transverse 

 system, or that between the inner and outer aspects 

 of the bark. 



That the electrical condition of the flower must be 

 energetic is to be inferred from its rapid growth. 

 The remarkable elevation of temperature which 

 occurs during the development of this organ, and 

 the important chemico-vital actions which take 

 place in it, should certainly excite corresponding 

 electrical phenomena. Nevertheless, almost nothing 

 is known on the subject. The only observations 

 are by the Italian observer Zantedeschi, who found 

 that at the period of flowering in the Tulip, Jonquil, 

 and Anemone a descending current occurs, and in 

 an Azalea, an Amaryllis, a Lily, and various species 

 of Opuntia, a current passing from the stamen to 

 the pistil. 



The electrical condition of the fruit has been as 

 little investigated. Donne found that in the Apple 

 and Pear a current would appear to pass from the 

 stalk towards the eye; whilst in the Peach and 











- 



Apricot the current passes in the contrary direction. 



T - - % r i Mr. Goodsir remarks that it might be well to de- 



n may, therefore, be presumed that in the act of I termine how far the 



ata ^k. A __. A _ #" a a ■- 



vegetation, after germination is accomplished, the 

 ascending sap, which communicates bv means of the 

 root with the soil, conveys to it continuously the 

 excess of positive electricity which it has acquired 

 during its course upwards in its reactions more par- 

 ticularly with the descending sap ; while the latter 

 furnishes to the air, by exhalation, its 

 negative electricity. 



As regards longitudinal electrical eurreiits in the 

 JJicotyledons Becquerel states that if the electrodes 

 of the galvanometer be inserted transversely into 



tile parenchyma of the bark, the one a certain 





of 





e opposite directions may be 

 referable to structural differences in the two fruits 

 examined : whether in the monocarpous form, the 

 Peach, the current be not referable to the centri- 

 petal current of the leaf ; and whether in the Apple 

 form (the fleshy mass of which is not a development 

 of the carpellary leaf, but of the cortical layer of 

 the receptacle, and of the end of the peduncle) it 

 is not due to the same causes which produce the 



general superficial, or cortical axial current in the 

 plant. 



An important question connected with these 

 observations is whether the currents arc derived 



posterior basal pinnules being considerably enlarged; the- 

 secondary pinnules are oblong, or linear oblong acute * r 

 they are pinnatifid, with short toothed segments. The 

 sori form a line around the margin of these segments, 

 where they are produce d abundantly. The rhizome is 

 creeping, and the fronds are lateral and adherent to it, 

 and grow up erect, with the leafy portion spreading- 

 It is a free-growing evergreen stove Fern. 



16. Drynaiua Fortuni, T. Moore, Genera and Species 

 ~oi Cultivated Ferns, ined. 



Fronds simple, lanceolate attenuate, subcoriaceous, somewhat nn* 

 dulnted, smooth, puncnilate with transparent dots; sori on the 

 upper part of the frond, uniserial near the costa; stipes arti- 

 culated with a creeping scaly rhizome. ,«, 



An elegant simple-ironded evergreen species, with the 

 appearance of a slightly undulated narrow Scolopen- 

 drium. The fronds are a foot or more in length, narrow 

 I strap-shaped lanceo'ate, attenuated both at the base and 



