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Show 206 I CIRCUl\1NUTATION OF STEMS. CHAP. IV. accompanying figure (Fig. 76) ~ivos the necessary particulars, n.nd shows that the stem Circumnutatod, though rather slowly. Fig. 76. Fuchsia (garden var.): circnmnutation of stem, kept m darkness, trace1! on horizontal gla&s, from 8.30 A.M. to 7 P.l\1. March 20th. Movement of bead originally magnified about 40 times, here reduced to half scale. (10.) Cereus spPciocissimus (garden var., somot~m~s called Phyllocactus multifl.orus) (Cactere, Faro. 109).- rh1s plant, which was growing vigorously from having been removed a few days before from the greenhouse to the h~t-house, was observed with especial interest, as it seemed so little probable that the stem would circumnutato. Tho branches aro flat,_or ftahelliform · but some of them are triangular in section, wJth the three sides hollowed out. A branch of this latter shape, 9 inches in lonO'th and H in diameter, was chosen for observa· tion, as lcRs lil;ely to circumnutato than a flaholliform branch. The movement of tho bead at tho end of tho glass fil~mcnt, affixed to the summit of tho branch, was traced (A, Fig. 7~) from 9.23 A.M. to 4.30 P.M. on Nov. 23rd, during which tim~ Jt changed its course greatly six times. On the 24th ano~ :~r tracing was made (see B), and the bead on this day change 18 course oftener, making in 8 h. what may be considered as .r~ur ellipses, with their longer axes differently directed. Tho poslt~on of the stem and its commencing course on the follom:.g morning are likewise shown. There can be no doubt that \~8 hraneh, though appearing quite rigid, circumnutated; but e CHAP. IV. CIRCUMNUTATION OF STEMS. 207 extreme amount of movement during tho time was very small, probably rather less than the ~th of an inch. Fig. 77. 1/ 23'a.7n. (\7 ~J ~.24~' A B. Cereus speciocissimus: circumnutation of stern, illuminated from aboYe, traced on a horizontal glass, in A from 9 A.M. to 4.30 P.M. on No\". 23rd; and in B from 8.30 A.lii. on the 24th to 8 A.l\I. on the 25th. Movement of the bead in B magnified about 38 times. (11.) Hedttra ielix (Araliacero, Fam. 114).-Tho stem is known to be apheliotropic, and several seedlings growing in a pot in the greenhouse became bent in the middle of tho summer at right angles from the light. On Sept. 2nd some of these stems were tied up so as to stand vertically, and were placed before a ~orth-east window; but to our surprise they were now decidedly heliotropic, for during 4 days they curved themselv_ es towards the light, and their course being traced on a ?onzontal glass, was strongly zigzag. During the 6 succeedmg days they circumnutated over the so.me small space at a slow rate, but there could be no doubt about their circumnutati? n. The plants were kept exactly in the same place before the 'Wln~ow, aud after an interval of 15 days tho stems were agam observed during 2 days and their movements traced, and |