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Show 35() 1\iODIFlEU Ulll 'UMNUTA'l'lON. CIIA't'. VII. pudica; but, from standing further apart, they do not overlap ono another nearly so much ns in this Jattor plant. The main petiole is CUl'ved slightly downwards <luring the day, but straightens itself at night. In throe ca ·os it rose from 3° above the horizon at noon, to 9° at 10 P.M.; from 11° to 33°; and from 5° to 33°-the amount of angular movement in this latter case amouutmg to 28°. In several other species of Coronilla tho leaflet showed only feeble movements of a similar kind. JJedysarum coronarimn (Tribe G).-The small lateral leaflets on plants growing out of doors rose up vertically at night, but the large terminal one became only moderately inclined. The petioles appnrently did not rise at all. Smith?:a Pfundii (Tribe G).-The leaflets rise up vertically, and the main petiole also rises con. iderably. Arachis hypog(w (Tribe 6).-The shape of a leaf, with its two pairs of leaflets, is shown nt A (Fig. 147); allCl a leaf asleep, Fig. 147. A B. Arachis lt!fpoqrea : A leaf rluring the day, ~cen from Ycrticallr aiJoYc i B, leaf a~le~p. ~een laterally; copied f'ro;n a photognph. F1gures much reduced. traced from a photograph (made by the aiel of alnminium light), is given at B. The two terminal leaflets twist round nt night until their blndes stand vertically, and approach each other until they meet at the same time moving a little upwards and backwards. The' two la.teral leaflets meet each ot ho r n· : th.e same manner but move to a greater extent forwards, that 18• !II a contrary direction to the i wo terminal leaflets, which .they partially embrace. Thus all four Jenflets form togethor.a sJDg~e J)acket with their edcros directed to the zenith, and WJth theJrt ' b l. h as no lower surfaces turned outwards. On a plant w 110 w 1 grow.m g v1. gorously the closed leaflets seemec1 t oo J ea vy for t IC 1 CnAP. VII. SLEEP OF LEAVE . 357 petioles to s~ppor~ them in a vertical position, so that each night the mam petwlo became twisted, and all the packets w exten~ed h?rizontally, with ~he lower surfaces of the leaflets e~~ one side directed to tho zeruth in a most anomalous rna . . t . t' d nne1. ThiS fac IS ~en Ion~ solely as a caution, as it surprised us gr~tly, unt_Il v:e discovered that it was an anomaly. The petioles are mchned up~nrds during the day, but sink at night, so as to stand at about nght angles with the stem. The am t of sm· km' g was measure d only on one occasion and found to ubn 39°. A petiole was secured to a stick at th~ base of th ~ e terminal leaflets, and the circurnnututing movement of ;no:~ ~~se .~e1afle~s wt adsftracecl from 6.40 A.M. to 10.40 P.M., the plnnt mgi umma e romabove. The temperature was 17o-17.'-o c. and therefore rather too low. During tho 16 h the le,.a t z t' . . • •• .ue lllOVeC t·h ricr·e up and thnce down, and as tho a cending and d ~ l mg mes d'd · . e~:~cenc - I not comcHlo, three ellipses were f01·med. ~esmodium gyrans (Tribe 6).-A large and full-grown lenf of th1s plant, so famous for the spontaneous ~ovements of the two little ln.teral leaflets, Fig. H8. IS he.re represented (Fig. 148). The large temunal !eafiet slee~s by sin king vertically down, whilst the petwlo rises up. Tho cotyledons do not sleep, but the first -formed lcnf sleeps equally well as the older ones. Tho appearan~e presented by a leeping branch nnd one m the day-time, copied from two r:otographs, are shown at A and B (Fig. 9), and we see how at night the leaves are cro~ded together, as if for mutual protec~ Jon, by the rising of the petioles. Tho ~tioles of the younger leaves near the summits of the shoots rise up at night . o as to s~d vertical and parallel to tl;e stem ; whilst those on the sides were found in four cases to have risen respectively 464 o 36° 20° and 19 ·5o b th · . ' ' Desmodium ,qyrans .· hi ' a ove e molmed positions W ch th h leaf seen from F . ey ad occupied during the day. above, reduced t;r Ins~ance, in the first of these four cases to one-half na- .e petwle stood in the day at 23o and at tural size. The mght at 69~o above the h .· ' I th minute stipules evening th · . onzon. n e unusually large. e rismg of the petioles is almo t completed be£ th 1 ore e eaflets sink perpendicularly downwards. .r I |