January 27, 1912.] 



THE GARDENERS' CHRONICLE 



49 



THE 



(imrbmcrs'Cbromti 



No. 1,309.— SATURDAY, January 27, 1912. 



escape of the water that kept them turgid, 

 these cells will at the same time, of course, 

 become somewhat smaller. If this escape 



triggers. When any one of these is 

 touched a change in the protoplasm 

 occurs, and an impulse is instantaneously 



of liquid is confined to the cells of one transmitted to the motile cells of the 



CONTENTS. 



side the necessary consequence will be 

 that the cells on the two sides will no 



Mu 



Acacia Baileyana ... 59 



Agricultural education... 58 



Apples, the colouring of 59 



Autumn tints, plant-, for 51 

 Beech trees in Ashritlge 



Park 56 



Benevolent Institution, 



Gardeners' Royal 56 & 62 

 Big-bud, spraying for ... 58 

 Books, notices of — 



Irish Farming World 57 

 The Orchid Review ... 57 

 The Orchids of New 

 Guinea ... .. 50 



Dimorphotheca auran- 



tiaca 52 



Drought and tree-growth 58 

 "Forestry and the Develop- 

 ment Grant 55 



Fruit trade of South 



Africa, the 58 



Fruit trees in grass land 60 

 hardeners, certificated 60 

 Oenetics, lectures on 57, 58 

 Hibiscus hybrids ... 57 



Iris stylosa 60 



Law note — 

 Action against a horti- 

 cultural society ... 63 

 Obituary — 



Bowler, John ... ... 63 



Murphy, Michael ... 63 

 Purves, Thomas ... 63 



Payne, Mr. C. Harman, 

 honour for 58 



Pineapple culture at 

 Oakbrook Gardens, 

 Hammersmith ... 59 



Pinguicula gypsicola ... 

 Plants, movement in ... 

 Plants, new or note- 

 worthy- 

 Calceolaria virgata ... 

 Rats, destruction of 

 Rhododendron Brough- 



tonii aureum 



Rosary, the — 



New Roses of the 

 N.R.S. •■ Catalogue" 



Rose Madame Hector 

 Leuilliot 



Trials at Bagatelle ... 

 Scotland, notes from ... 



Small holdings 



Societies — 



Gardeners' Royal 

 Benevolent Institu- 

 tion ... 



North of England Hort. 



Royal Horticultural ... 



Scottish Horticultural 



Ulster Horticultural ... 

 Sweet Pea, diseases of.. 

 Sweet Pea Senator Spen- 

 cer 



Vitex Agnus-castus 

 Ward, Mr. William 

 Weather in 1911, the ... 

 Week's work, the— 



Flower garden, the ... 



French Garden, the ... 



Fruits under glass ... 



Hardy fruit garden ... 



Kitchen garden, the ... 



Orchid houses, the ... 



Plants under glass ... 



58 

 49 



50 



59 



53 



the same occurs in Mimosa, where, as is 

 longer be equal in size, and the organ will well known, injury to one of the leaflets 

 bend over towards the flaccid side. One causes an impulse to travel down the leaf- 

 may illustrate this bending movement by stalk, with the result that the pairs of 

 damping a sheet of paper on one surface, leaflets are successively affected and 

 when it will be observed to curl up with change their positions. The movement has 

 the damp side outermost. This is because 



50 



59 

 51 



58 



58 



been very clearly shown to depend, in 

 the water forces its way between the par- this plant, on the exudation of the watery 

 tides of paper, and so causes a swelling solution of salts from the cells concerned 



of the area affected. If the sheet of paper 



There are very many other examples 



62 

 63 

 60 

 63 

 63 

 52 



60 

 52 



57 

 58 



54 

 55 

 55 

 54 

 55 

 54 

 54 



be totally immersed in water it becomes which might be quoted of what we may 



flat again, because the water has caused term vital movements, inasmuch as they 



the whole piece to swell equally. Simi- depend on the living active protoplasm for 



larly, if the wet sheet be held in front of their occurrence, but space will not allow 



a fire, it will curl so that the surface next of their being dealt with here. 



the grate will be concave, because the 



A further series of plant movements de- 



^ ■ 



water is evaporating faster from this than pends upon certain physical properties of 



from the outer side. the water which is present in the cells con- 



^ We can easily prove that this difference cerned in producing those movements, 



in water content is the substantial reason To this series belong those movements 



why a Tulip flower, for example, opens which result in splitting open the 



petal should be anthers of a stamen, in scattering the 



picked from a moderately young flower and spores of a Fern or a Selaginella, or in 



in a warm room. 



A 



ILLUSTRATIONS. 



Acacia Baileyana 



Beech, a veteran ... ". 



Beech "The Queen," in Ashridge Park (Supplemen- 

 tary Illustration) 

 Calceolaria virgata in the rock garden at Kew ... 



Rhododendron Broughtonii aureum 



"Vitex Agnus-castus 



dispersing the contents of the " fruit " of a 



59 

 57 



to 



50 

 52 



MOVEMENT IN PLANTS. 



r PHE day has long gone by when the easily. By transferring the slice to 



plant could be contrasted with the 



a longitudinal slice be cut out of the 



middle with a sharp knife. If it is put into liverwort. It is a remarkable fact that 

 a glass of water the slice will, in about when a liquid is contained in a per- 

 fectly closed vessel, the walls of which 

 it can wet, it demands tremendous force 

 to break the continuity of that liquid. 

 The reason why this fact was long un- 

 known is largely due to the need of com- 

 plete cleanliness in the apparatus and 

 liquid used for experimental investiga- 



the sense of closing the petal. This is be- 

 cause the cells on the outer side have the 

 capacity of taking in water and swelling 

 more than those on the inner side. But 

 these same cells also part with water more 



another glass containing a weak solution tion. 



animal as an organism devoid of (3 or 4 per cent.) of common salt, water is 

 movement, but few people perhaps are withdrawn from the cells of the slice, but 

 aware of the important part which motile much more quickly from the cells of the 



fact 



organs of various kinds actually play in the outer (lower) 



side, 



and 



the 



slice 



economy of plants. We are most of us straightens out. It is possible to repeat 

 familiar with the numerous manifestations this experiment with the same slice 



a 



grouped as sleep movements, and are number of times, and the result is always 



aware that the leaves of Clover, False the same. The straightened-out position 



Acacia, and of many other trees and herbs, is reached as soon as the salt has with- 



assume a very different position at night drawn the excess of water from the cells 



from that which they maintain during the that previously kept them turgid, 

 daytime. Again, the rapid, and often un- These experiments show that 



desired, opening out of Tulip or Crocus mechanism of this sort (and it applies to 



of this great coheeiveness of water was 

 largely due, in the first instance, to 

 botanical researches on the behaviour of 

 water in plants. 



This is not the place to attempt to dis- 

 cuss the evidence on which our knowledge 

 of this property of liquids is based, and it 

 must suffice to say that in the case of water 

 present in plant cells it is not possible, 

 provided air is excluded from passing 

 through the walls, to cause a space to ap- 

 in a pear without exerting a force of hundreds 



ij^ . , -, . , „ , . - -^*~ — of pounds to the square inch. Bearing this 



flowers m a warm room and their closure nearly all the mechanisms in which living in mind then, it will be seen that if water 

 *faen the temperature falls, is a feature protoplasm is concerned), the movement evaporates from such a cell, and air cannot 



get in to take its place, the wall must be 

 subjected to a tremendous pull, and any 

 weaker part of it will tend to be sucked 



known to many people who, nevertheless, depends on a disturbance of equilibrium 

 would be puzzled to explain how the between the forces tending to stretch each 

 ■change is brought about. Dionaea musci- 

 pula (Venus' s Fly-trap), Mimosa pudica 



surface to the uttermost. 

 But we do not know why or how it comes 

 < ' Humble " or Sensative Plant), and about that the protoplasm shows this 

 some species of Oxalis afford examples of difference of sensitivity on the two sur- 

 moyements which, in their rapidity of exe- faces. Indeed, whenever we try to get 



inwards. 



cution, accord but ill with our general 



conception of the lethargic vegetable and any manifestation of life, we are always 



suggest rather, the lively animal. All prevented from penetrating further into 



these movements depend primarily upon the mystery because we do not know 



the living protoplasm, which is arranged enough about the protoplasm itself. 



m such a way as to provide the mechanical In the Sensitive Plant and the Venus's 



Now, in the light of this, the structure 



of the anther, so far as its opening 



mechanism is concerned, becomes intelli- 



behmd the immediate physical cause of gible. Just below the epidermis is the so- 



means that render them possible. Briefly 

 explained, the motile structure consists of 

 cells which are lined internally with proto- 

 plasm, and each cell contains so much sap 

 that it is kept very tensely expanded. 

 JNow if W e imagine that the cells which 

 compose one of the two longitudinal halves 

 of any organ, say the base of a leaf-stalk, 

 a*e suddenly rendered flaccid by the 



called fibrous cell layer which is respon- 

 sible for the dehiscence, or splitting open, 

 of the pollen sac. The individual cells of 

 this layer form a sheet of tissue, inter- 

 rupted by a line usually running parallel 

 with, and between, the two pollen sacs 

 situated on each side of the stamen which 

 before, on a difference of turgidity on the forms the line of dehiscence. 



Fly-trap the mechanism is more compli- 

 cated. The actual movement depends, 



part of the two surfaces of the motile 

 organ, but the mechanism may be actuated 



The cells themselves are constructed on 



the strictest mechanical principles. 



The 



by stimulating another part of the plant. otherwise thin membrane is thickened to- 



In the Fly-trap the stiff hairs (three or wards the pollen cavity, whilst prongs or 



four on each leaf lobe), situated on the bars of thickening also extend over the side 



upper surface of the leaf, form the walls, leaving the intermediate portions 



r*o. Bqi, Garden 



1Q19 



