[63]

Acanthus mollis

Jun 14' to morning of 16' 1878

Young Plant with only 2 leaves, younger ones with petioles 2 1/4 long— apex 11 inches from vertical glass, under skylight [sketch]

See Tracing: leaf falls from early in morning till about 3° P.m, & then rises till 11° P.m & during large part of night. —Circumnutation admirably distinct.

Ascending & descending lines do not coincide. (47 Hours)

Temp on 14' 16° to 16 1/2 C. — 15th 15° to 15 1/2 C.

(19) A.m. Acanthaceæ (Fam. 168) p. 316

A seedling plant had produced only 2 leaves, the younger of which, was, 2 1/4 long, petiole included, was observed during 47h. All On each all 3 3 mornings the apex of the leaf fell & in the 2 days when observed continued to fall till 3 P.m, & then rose considerably, continuing to rise on the second night until the early morning; but but falling on the first night it fell during the first night instead of rising.

We can have little doubt that this was an anomaly movement, due either to the leaf not having as yet fully adjusted itself to the light from above, & it may seem that the whole tracing closed on a higher level this day than on the next 2 to the leaf having really risen more greatly during the night & having when first closed in the morning already fallen much. when the first observation was made. We have further reason to believe that the fall this to have been case during the night was in evening, because we found by morning the distance of the apices of the opposite of a with a seedling young plant of an allied Spec. (A. spinosus), that they leaves each leaf the leaves certainly rose at night 10 1/2° between noon & 10. 15 P.m

This rise was chiefly or exclusively due to the straighten & rising of the blade itself & not to the reversal of the petiole. We may thus conclude that the leaves of A. rose periodically falling in morning, & rising in the afternoon & night.—