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Jun 22d & 23d 1878

Cycas pectinata

circumnutation of Leaflet (Fam 224)

We have seen that the young leaf circumnutates as soon as it breaks through the soil. After it had grown to height of 11 1/2 inches & as soon as the leaflets had uncurled, one of the terminal pairs 3 3/4 in length observed under skylight. It was much bowed & 3 3/4 in length, but with the terminal portion only a little below horizontal.—

Apex of leaf 7 3/4 from vertical glass. (22d Temp 19-21 C. on 23) 21° C.

See Tracing— Movements strongly pronounced — Leaflet sinks all day from 6° 40' in morning to at least 7° 15 P.m & sometime after this latter period rises during the night so as to stand at former level by 6° 40' on following morning.— The leaflet is descending zig-zag in conspicuous manner showing that modified small circumnutation & the ascending & descending lines do not coincide showing circumnutation modified by a diurnal & nocturnal up & down movement, just in way in which circumnutation is modified by Heliotropism & geotropism.

(A young leaf 11 1/2 inches in height of which had the leaflets had nearly uncurled was observed during 48 hrs with the petiole secured to a [illeg] of the base of the 2 terminal leaflets. One of these— down which was 3 3/4 in length Had A filament was fixed: to one of the 2 terrestrial leaflets it was much bowed downward, but with the apex upturned, so that the filament was projected almost nearly horizontally. The petiole at this bases being secured The the movements of the leaflets Fig are strongly marked or longer in extent & periodical, for the leaflet it fell until alm 7 P.m & rose during the night falling again next morning after 6. 40 a.m. The descending lines are were are strongly in a marked manner zig-zag, & this indicates that the great descending & no doubt ascending movements are due to modified circumnutation.—