Page:The New International Encyclopædia 1st ed. v. 14.djvu/104

MOVABLES. is practically synonyiiious with personal prop- erty ill American and Knglish law. See Chat- tel; Personal Pkopebty; Real Peopertv. MOVEMENT. Several modes of movement arc manifested in plants and plant organs. Some of the lower forms (bacteria, alga", and fungi) exhibit movements of locomotion in cer- tain stages, swimming freely in the water in which they are found. The same is true of the zoiispores and conjugating se.xual cells (gametes) of many plants whidi themselves are not motile. Also, the Plasmodia of slime molds show a peculiar flowing of the protoplasm which results in motion from one place on the substratum to another. This is called amoeboid movement. An- other kind of movement often met with in plants is the so-called hygroscopic movement. This is sliowii by the awns of certain grasses and other fruits ('seeds') (Fig. 1.), by the valves of many seed-pods (Fig. 2.), by the teeth of the peristome of moss capsules, and by the elaters of liverworts, horsetails (Equisetum), etc. It is a phenome- non having no connection whatever with the vitality of the parts, being due merely to un- equal swelling or shrinkage (i.e. warping) of the different tissues by reason of their unequal absorption or loss of water; and this depends on the un- like composition of the ma- terial of the cell walls. From a physiological point of view perliaps the most important form of plant movement is that exhibited 78 MOVEMENT. and forward, while the whole leaf sinks (Fig. 3). If a shock be given to one pinnule, the disturb- ance there set up. if severe enough, is propagated to other parts of the same leaf and even to other Fit;. 2. HYGROSCOPIC MOVEMENTS OF THK VALVES OF SEED PODS. 1, Campaniihi nipiiDruIoitles ; a, when dry ; h, when wet; 2, Linaria Mnredonica : a, dry; />, wet. leaves. Almost any portion of the plant can receive a stimulus in this way and pass it on to other regions. The organs which execute the visible response are motor organs (q.v. ). cushions Flo. 1. FRriT OF EROUIUM (JltUlNUM. H, When wi't ; h. wIhmi iJry ; tbi- HtriLlKlitcuiiiK ot /, when ttp ts caught in Krnt«H and thp nwii aliHorhs moisture tioD's the seed enntatulnK lower part into the soil, and so 'plants' it. by the leaves of the so-called sensitive plants. The l)est example of this is found in the Mimosa of greenhouses. When this plant is jarred, struck, locally l>urned. or injured other- wise, its leaves suddenly collapse, even those at a distance from the shock. Its leaves an? doubly compound, and in closing the pinnules rise so that the upper faces of opposite ones are brought together, the pinnie drop downward Km;. 3. LEAF OF THE SENSITIVE PLANT {Mimosa). II, U light when undisturbed ; b, utter shulilng. of tissue (pulvini) situated one at the base of the leaf, of each pinna, and of eacli |)innule. Indigenous plants which show this reaction, though not so strikingly, are the common oxalis and dilTcrcnl species of Cassia. The so-called "sleep movements' of leaves of the pea family. Oxalis, etc., are executed by the same motor organs, which, however, arc often less per- fectly developed. These movements consist of changes in the position of the leaf following variations in the intensity of illumination, so that these leaves have a ncxturnal and a diurnal