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Show 352 MODIFIED IR Ul\INU'l'ATION. CHAP. VII. rved broken line. The terminal leaflet, therefore, of this ~;ecics' described during the daytime ?nly ~ single additional ellipse, m tcau of two au- Fig. H-3. ditional ones, as in the I I -~.· . :.; k:~ ~!w~::~£;i~ fourth chapter th<tt the stem circumnntates, as no 1 · doubt docs tl10 main petiole )' ,'f m1d the sub-petioles; so A -r")'J ,......-/ that tho movement repre- . Bunted in fig. 143 is a com- ,.· ......... / pounded one. We tried .r···· to ob::;erve the movements -- of a leaf kept during the ... ..-- day in darkness, but it · .... e ··:·· . . b gnn to go to sleep after 1hfolium rcsuprnatum: CJrcum~utnt!On 2 J 15 m. and. this was and nyctitropic movements of the tcr- L , . minal leaflet during 24 hours. well pronounced. after 4 h. 30m. '[1·ifolium repens.-A tom wa. secured clo. e to t~e base of a moderately old leaf, and tho mov ment of. th.e termi~alleafiet was ob. erved during two days. TltiR ca e IS mtcre~tmg solely. from the simplicity of the mov mcnts, in contrast w1th those of the two preceding pecie . On the first day the leaflet fell hetwc n 8 A.M. and 3 P.M., and on tho second between 7 A.M. and 1 P.M. On both days the u cu11cling course was ~omewbat zigzag, and this evidently repr?sc11ts ~he circUI~nutatmg m~~e~ ment of the two previous spe01es dunng the mJcld.le of t~le lJ Yt After 1 p M Oct 1st (Fig. 14.4) the leaf-let began to nse, . u tho movc~~~t w~s slow 011 both days, both before and af~er this hour until 4 P.M. Tho rap1. d ovenm· g an c1 noctur.n al nse 24 b then com~encecl. Thus iu thi::; species the com~o dunngf t ~ consists of a single great ellipse; in 'l'. r·esupmatum 0 d\\ ellipses one of which includes the nocturnal moveroen.t an \ much ~longatcd; and in '1'. subten·anell?n of three ellipses, o which the noctumal one is likewise of great length. . h t nd Secu1·igera co'l'om.l .l a (Tn'1 lO 4) .-Tl le l.e aflets ' wlu.c s a 1 t como opposite one another and are numerous, rise up at mg 1 ' le into close contact, and bend backwards at a moderate ang towards the base of the petiole. CHAP. VII. SLEEP OF LEAVE'. 350 Lot11s (Tribe 4).-The nyctitropic movements of 10 species in this genus were observeu, and found to be the same. The· main petiole rises a little at night, and the throe leaflets rise till they become vertical, and at the same time approach each other. This was conspicuous with L. Jacobreus, in which the leaflets are almost linear. In most of the species the leaflets rise so much as to press against the stem, and not rarely they become inclined a little inwards with their lower surfaces exposed obliquely to the zenith. This was clearly the case with L. mafor, as its petioles are unusually long, and the leaflets are thus enabled to bond further in wards. The young leaves on the summits of the stems close up at night so much, as often to resemble large lmds. The stipule-like leaflets, which are oftc11 of large size, rise up like the other leaflets, and press agai11st the stem (Fig. 145). All the leaflets of L. Gebelii, and probably of the other species, are provided at their bases with distinct pu1vini, of a yellowish colour, and formed of very small cells. The circumnu tation of a terminal leaflet of L. pe1·igrinus (with the stem secured) was traced during two days, but the movement was so simple that it is not worth while to give the diagram. Tho leaflet fell slowly from the early morning till about 1 P.M. It then rose gradually Fig. 144. f'"\l I ; '(' t Trifolium rcpens: circulllnutatiounn<. l nyctitropi( mo,·cments of a nearh· full- grown termin;{l leatlet, traced on a vertical glass from 7 A.~L Sept. 30th to 8 A.M. Oct. 1st. octurn<tl course, represented by curnd broken line, much nl•breviate<. l. at first, ?ut l'apidly late in the evening. It ~IOnal~y stood still for about 20m. during tho day, and sometimes Zigzagged a little. Tho movement of one of the basal, stipule-like leaflets was likewise traced in the samE> ~anner and at the same t.ime, and its course was closely similar 0 1 that of the terminal leaflet. of anp eT .r ibe . 5 of Bentham and Hooker, tho sleep-movementR Cles lD 12 genera have been observed by our:elves and 2 A ., I |