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Bignonia capreolata (Apoheliotropism)

July 19-20 1878 Anheliotropism (Helioapotropism)

A vigorously young plant with 2 tendrils standing up vertically had its long flexible stem (see Climbing Book) secured to stick close to base of tendrils—on right-Hand one Each t. terminates in 3 sub-branches, & has 2 lateral branches, each with 2 sub- branches— Plant protected from light at top & on all side except front facing N.E. window. Right-Hand t a little triangle of paper was affixed to tip of one sub-branch of the lateral tendril branch, & another little mark triangle was fixed to one of the 3 terminal sub-branches of Left-Hand t. A mark was fixed beneath & in front at such distances that movem tracing diminished in whilst t. stood vertical, but of course increased exaggerated as tracing become oblique on Horizontal glass.—)

Left-Hand t. Tracing Tracing. I. Between 7° 35' 'a.m & 10° 35' P.m (19th) & the in this interval, moved from vertical to horizontal position, pointing directly from light ie 90° : During night moved a little bit to light, & next day (20th) in very slightly zi. in almost straight line from light till 5° P.m; at which period the t. converged & touched opposite one, pointing from light & a little downwards— During the 19th or first clearly circumnutated between 9° 20' & 3° & then moved in very very zig-zag line.—

Right Hand T. Cour Course during 19th like other t. but circumnutation between 9° 20' & 3° not so strongly marked— During night moved very

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Bignonia

little. Next day followed same general course as other tendril but circumnutated plainly plainly till 7° 30' P.m, when both t. were locked together & the mark behind cd not ha be seen on account of the stick to which stem was tied. (N.B. on morning of 20th the mark had to be changed in position, so as to bring tracing on to glass— but the tracings of the 2 days have been joined together.

Right-Hand t. on m. At. 6° 45' a.m. July 21' the pot was turned completely round, so that the tendrils now pointed to light; but as the 2 were interlocked, the left one was tied down & movement movement of Right one traced as before. (See 111.) The t again moved from light but now in nearly equable curve with very little zig-zag — till 5° 45' P.m. (N.B at 4° P.m. position of mark had to be changed) The t. then stood at right angles— to light. — after 8° 5° 45' P.m it travelled back to light side, evening then dusky & so during night. But on morning of 22d it again travelled from light, still hardly at all zig-zagging & at night had no power of moving back.) (Altogether movement closely analogous to Heliotropism, (ie modified circumnutation) except that the mvmt from light endure for considerably long time after true circumnutation has ceased.)