[75]

Dec. 28th 1878— Passiflora gracilis

(Effects of Light on circumnutation of tendril)

Very young plant, wh in Hot H. had been rather more illuminated on one side than other was reversed & during warm clear day placed before N.E. study window, & movement of tendril traced (see fig.) on horizontal glass— sides & top darkened, left open behind to room so that light in front not too bright.— Stem secured to stick, (with paper mark on top) close to base of tendril, & tip of tendril & this mark mark wa afforded means of observation— Traced from 8° 15' a.m to 10° 50' P.m, by which time t. bowed & growing old.

In tracing the broken line show approximate course when off glass, made about 4 Ellipses, the last one very small. If we consider point of commencement & close; there is hardly any evidence of ordinary heliotropism.

Dec. 30th I observed another & very young tendril during whole day, but it made only an one ellipse transverse to direction in which light entered; but the t. was so much bowed downwards the whole day, that tracing not trustworthy