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Show 252 CIRCUMNUTATION OF LEAVES. CHAP. lV. quite fully grown, produced by a lateral shoot, on a young tree 3 feet in height, were observed during 29 h. (July 31st), in the same manner as the leaves of the previous species. Both these leaves certainly circumnutated, maldng within the above period two, or two and a half, small, irregular ellipses. Fig. 114. \ \ \ I ~ \ I 1J ~ i\ n ~~ f! I! If t Gycas pectinata : circumnutation of one of the (26.) Cycas pectinata (Cycadero, Fam. 224).- A young leaf, lH inches in length, of which the leaflets had only recently become uncm·lcd, was observed during 4 7 h. 30 m. The main petiole was secured to a stick at the base of the two terminal leaflets. To ono of the latter, 3l inches in length, a filament was fixed ; the leaflet was much bowed downward, but as the terminal part was upturned, the filament projected almost horizontally. The leaflet movccl (see Fig. 114) largely aud periodically, for it fell until about 7 P.M. and rose during the night, falling again next morning after 6.40 A.M. The descending lines are in a marked manner zigzag, and so probably would have been the ascending Jines, ifthey had been traced throughout the night. terminal leaflets, traced CIRCUMNUTATION OF LEAVES: from l:l.30 A.M. June 22nd to 8 A.M. June MoNOCOTYLEDONS. 24-th. Apex of leaflet 7i inches from the ver- (27.) Canna Warscewiczii (Cannacere, tical glass, so tmcing Fam. 2).-The movements of a young not greatly magnified, leaf, 8 inches in length and 3~ in and here reduced to · one-third of original breadth, produced by a v1gorous young scale; temp.19°-21°C. plant, were observed during 45 h. 50 m., as shown in Fig. 115. The pot was slided about an inch to the right on the morning of tho 11th, as a single figure would have been too complicated; b~t the two figures are continuous in time. The movement 1. 8 periodieal, as the leaf descended from the early morning until about 5 P.M., and ascended during the rest of the evening and CHAP. IV. MONOCOTYLEDONS. 253 part of the night. On the evening of the 11th it circumnutated on a small scale for some time about the same spot. Fig. 115. (/p// A. B. ! / ?i' Canna Warscewiczii : circumnutation of leaf, traced (A) from 11.30 A.llf. June lOth to 6.40 A.M. 11th; and (B) from 6.40 A.n1. 11th to 8.4-() A.M. 12th. Apex of leaf 9 inches from the vertical glass. (28.) Iris pseltdo-acorus (Iridere, Fam. 10).-Tho movements of a young leaf, rising 13 inches above the water in which the plant grew, were traced as shown in the figure (Fig. 116), during 27 h. 30 m. It manifestly circumnutated, though only to a small extent. On the second morning, between 6.40 A.M. and 2 P.M. (~t which latter hour the figure here giVe~ ends), the apex changed its course fi:e times. During the next 8 h. 40 m. it Zigzagged much, and descended as far ~ ~he }(:)west dot in tho figure, making In I~ course two very small ellipses; but If these lines had been added to the diagram it would have been too complex. F (29.) Orinum Capense (Amaryllidero, Fig. 116. Iris pseudo-acarus: circumnutation of leaf, traced from 10.30 A.nf. May 28th to 2 P.llf. 29th. Tracing continued to 11 P.M., Lut not here copied. Apex of leaf 12 inches beneath the horizontal glass, so figure considerably magnified. Temp. 15°-16° C. am. 11).-The leaves of this plant are remarkable for theil· great length and narrowness : one was measured and found to be 53 inches long and oalnmlyo s1t· 4 br o~ d a t the base. Whi.l st qm.t e young they stand up vertically to the height of about a fuot; afterwards |