(9.) Vicia faba (Leguminosae, Fam. 75).—­A young leaf, 3.1 inches in length, measured from base of petiole to end of leaflets, had a filament affixed to the midrib of one of the two terminal leaflets, and its movements were traced during 51 ½ h.  The filament fell all morning (July 2nd) till 3 P.M., and then rose greatly till 10.35 P.M.; but the rise this day was so great, compared with that which subsequently occurred, that it was probably due in part to the plant being illuminated from above.  The latter part of the course on July 2nd is alone given in the following figure (Fig. 100).  On the next day (July 3rd) the leaf again fell in the morning, then circumnutated in a conspicuous manner, and rose till late at night; but the movement was not traced after 7.15 P.M., as by that time the filament pointed towards the upper edge of the glass.  During the latter part of the night or early morning it again fell in the same manner as before. [page 234]

As the evening rise and the early morning fall were unusually large, the angle of the petiole above the horizon was measured at the two periods, and the leaf was found to have risen 19o

Fig. 100.  Vicia faba:  circumnutation of leaf, traced from 7.15 P.M.  July 2nd to 10.15 A.M. 4th.  Apex of the two terminal leaflets 7 1/4 inches from the vertical glass.  Figure here reduced to two-thirds of original scale.  Temp. 17o — 18o C.

between 12.20 P.M. and 10.45 P.M., and to have fallen 23o 30 seconds between the latter hour and 10.20 A.M. on the following morning.

The main petiole was now secured to a stick close to the base [page 235] of the two terminal leaflets, which were 1.4 inch in length; and the movements of one of them were traced during 48 h. (see Fig. 101).  The course pursued is closely analogous to that of the whole leaf.  The zigzag line between 8.30 A.M. and 3.30 P.M. on the second day represents 5 very small ellipses, with their Fig 101.  Vicia faba:  circumnutation of one of the two terminal leaflets, the main petiole having been secured, traced from 10.40 A.M.  July 4th to 10.30 A.M. 6th.  Apex of leaflet 6 5/8 inches from the vertical glass.  Tracing here reduced to one-half of original scale.  Temp. 16o — 18o C.

longer axes differently directed.  From these observations it follows that both the whole leaf and the terminal leaflets undergo a well-marked daily periodical movement, rising in the evening and falling during the latter part of the night or early morning; whilst in the middle of the day they generally circumnutate round the same small space. [page 236]

(10.) Acacia retinoides (Leguminosae).—­The movement of a young phyllode, 2 3/8 inches in length, and inclined at a considerable angle above the horizon, was traced during 45 h. 30 m.; but in the figure here given (Fig. 102), its circumnutation is shown during only 21 h. 30 m.  During part of this time (viz., 14 h. 30 m.) the phyllode described a figure representing 5 or 6 small ellipses.  The actual amount of movement in a vertical direction was .3 inch.  The phyllode rose considerably between 1.30 P.M. and 4 P.M., but there was no evidence on either day of a regular periodic movement.