372 



CASSELL'S POPULAE GAEDKNING. 



universal, though, of course, materially modified hy 

 circumstances. 



Growtli Movements.^ — Connected with these 

 variations in the direction of growth are certain 

 movements. The wriggling movements of the tips 

 of the roots during their period of active growth 

 have heen previously alluded to as among the most 

 marvellous and, till lately, little suspected phenomena 

 of plant-life (Vol. I., p. 86). Similar movements 

 take place in all parts where active growth is going 

 on, and where circumstances do not prevent them. 

 If the tip of any fast-growing shoot he continuously 

 examined, it may he observed to move through a 

 circular or elliptical orbit with more or less rapidity. 

 Even the leader shoots of Conifers, which appear so 

 rigid, win be found, if watched from time to time, 

 to move round from point to point. A simple 

 method of observing this is to procure a circular 

 piece of cardboard marked with degrees and per- 

 forated in the centre. Pass the leader shoot of the 

 tree carefully through the hole in the card, so that 

 the shoot may have free play, and fix the card to 

 one end of a stake, inserting the other end in the 

 ground, or even tying it to the stem of the tree 

 below the leader. When the card is so fixed, note 

 the time, and mark with a pencil upon the card the 

 position of the end bud of the shoot and the direc- 

 tion in which it points. After an interval, repeat 

 the observation, when the shoot will be found to 

 have shifted its position, and it will continue to do 

 so day and night for some weeks during the period 

 of active growth. Of course, by more delicate means 

 in the laboratory, the direction and amount of move- 

 ment can be more accurately traced, and even made 

 to register itself, but the above method is amply 

 sufficient to establish the fact. 



Clim'bing Plants. — ^The phenomena exhibited 

 by climbing and twining jjlants, where the free- 

 growing shoots are found to swing round from point 

 to point, till at length they come in contact with 

 something around which they twine and support 

 themselves, are explained in like manner, the growth 

 in such cases being checked on the one side and 

 continued on the other, so that the point of the shoot 

 is thus made to travel round the support. The free- 

 gi'owing ends of such shoots exhibit sensibility to 

 touch just as the tips of the roots do. See Vol. I., 

 p. 87 ; and for a full account of various degrees of 

 sensibility and of movement in plants, sometimes so 

 perfect as almost to suggest a, degree of consciousness 

 and voluntary effort on the part of the plant, sec 

 Darwin's works on " The Power of Movement in 

 Plants," and on " The Movements and Habits of 

 Climbing Plants." 



Such facts as these, with many others that might 

 be cited, suffice to impress the notion that all the parts 

 of a plant in active growth are in a state of movement. 

 Arrested or suspended in one part, it manifests it- 

 self in another ; rekxed at one time, it is the more 

 active at another. Invisible to the naked eye, 

 except in the cases we have mentioned, it is stiU 

 certainly going on beneath the surface. It occurs 

 in the fluids of the living cells, in the constantly 

 mobile protoplasm, even when it is not traceable on 

 a large scale.. Truly, in the plant, as in th« animal, 

 life and motion, motion and life are inseparable ! 



FEENS. 



Br Jaues Bhitten, F.L.S. 



The Onooleas. — According to some authorities 

 the only plant included under the generic name 

 Onoclea is 0. sensibilis, frequently called the Sen- 

 sitive Fern, but having no claim to this name 

 beyond the fact of its speedily withering when cut. 

 In the "Synopsis FUicum," however, the Ostrich 

 Fern, Siruihiopteris, is merged as a section into 

 Onoclea, so the latter genus, as understood here, com- 

 prises three species — 0. Germanica (perhaps more 

 widely known as Struthiopteris Germanica), 0. orien- 

 talis {Struthiopteris m-ientalis), anAth.^ one mentioned 

 at the commencement of these notes. They are large- 

 growing herbaceous ferns, quite hardy in this 

 country, and make distinct and striking objects in 

 • the out-door fernery. All are dimorphic, that is to 

 say, the fertile fronds are unlike the sterile ones. 

 These latter, in 0. sensibilis, rise separately from the 

 naked, extensively - creeping root - stock, are long- 

 stalked, bright green in colour, broadly triangular 

 in outline, deeply cut into lance- oblong pinna>, 

 which are entire or wavy toothed. The fertile 

 fronds are twice-pinnate, much contracted ; the pin- 

 nules short and revolute, usually so rolled ujj as to 

 be converted into berry-shaped closed involucres, 

 filled with sporangia, and forming a one-sided spike 

 or raceme. The Sensitive Fern is one of the most 

 distinct of all hardy ferns, and it should be allowed 

 plenty of room to develop and display its peculiarly- 

 formed bright green fronds. It likes a soil rich in 

 vegetable matter, and should be planted where it is 

 constantly moist ; it is common in the United States 

 and Canada, and also occurs in North Asia, Amur, 

 Japan, and Manchuria. 0. Germanica is widely dis- 

 similar in habit from the last-named species ; it is 

 remarkable for its handsome and symmetrical mode 

 of growth — the fronds gi'owing erect in a circular 

 tuft from the short upright caudex, the large sterile 

 ones forming the outer series, the inner being formed 



