Chap. IV 



DICOTYLEDONS. 



237 



Fig. 104. 



(12.) Echeveria stolonifera (Crassulacese, Fam. 84). — The older 

 leaves of this plant are so thick and fleshy, and the young ones 

 80 short and broad, that it seemed 

 very improbable that any oircttm- 

 nutation could be detected. A fila- 

 ment was fixed to a young upwardly 

 inclined leaf, '75 inch in length and 

 ^8 in breadth, which stood on the 

 outside of a terminal rosette of leaves, 

 produced by a plant growing very 

 vigorously. Its movement was traced 

 during 3 days, as here shown (Fig. 

 104). The course was chiefly in an 

 upward direction, and this may be 

 attributed to the ehmgation of the 

 leaf through growth ; but we see that 

 the lines are strongly zigzag, and that 

 occasionally there was distinct cir- 

 cumnutation, though on a very small 

 scale. 



(13.) Bryophyllum (vel Calanchce) 

 calycinum (Crassulacese). — Duval- 

 Jouve ('Bull. Soc. Bot. de France,' 

 Feb. 14th, 1868) measured the dis- 

 tance between the tips of the upper 

 pair of leaves on this plant, with the result shown in the following 

 Table. It should be noted that the measurements on Dec. 2nd 

 were made on a different pair of leaves : — 



Echeceria stolonifera ; circum- 

 nutatioQ of leaf, traced 

 from 8.20 a.m. June 25th 

 to 8.45 A.M. 28th. Apex 

 of leaf 12J inches from the 

 glass, so that the movement 

 was much magnified; temp. 

 23°-24J° C. 



We see from this Table that the leaves stood considerably 

 further apart at 2 p.m. than at either 8 a.m. or 7 p.m. ; and this 

 shows that they rise a little in the evening and fall or open 

 in the forenoon. 



(14.) Drosera, rotundifoUa (Droseraceae, Fam. 85). — The move- 

 ments of a young leaf, having a long petiole but with its tentacles 

 (oi gland-bearing hairs) as yet unfolded, were traced during 

 47 h. 15 m. The figure (Fig. 105) shows that it circumnutated 

 largely, chiefly in a vertical direction, making two ellipses eacb 



