501 MODIFIED CIKCOIXUTATION. Chap. X 



peduncles bend downwards, and this is due to epinasty; foi 

 on two ixwisions ■wben puts were laid horizontally, the s\ilv 

 peduncles asisumed the same position relatively to the main 

 peduncle, as would have been the case if they had remained 

 upright; that is. each of them formed with it an angle of 

 about J:0' If they had l>een acted on by gootropism or aphelio- 

 tropism (for the plant was illuminated from alx>ve). they wuuld 

 hare directed themselves to the centre of the earth. A main 

 peduncle W!\s secured to a stick ii\ an upright jxisition, and ono 

 of the upright sub-peduncles which had lieen ol>served circum- 

 nutating whilst the flower was expanded, continued to do so for 

 at least '24 h. after it had withei-ed. It then began to Ixnid 

 downwards, and after 36 h. pointeii a little beneath the horizon. 

 A new figure was now begun i,A. Fig. ISS), and the snb-peduncle 

 was traced descending in a zigzfig line from 7.'20 p.m. on the 19th 

 1 1 9 A.M. on the ilud. It now pouitcd almost perpendicularly 

 downwards, and the glass filament had to be removed and 

 fastened transversely across the base of the young capsule, 

 "^^'e expected that the sulvpeduncle would have been motionless 

 in its new position ; but it continued slowly to swing, like a 

 pendulum, from side to side, that is, in a plane at right angles 

 to that in which it had descended. This circumniitating move- 

 ment w:is observed from 9 a.m. on '2'2iid to 9 a.m. •2t:th, as sho'mi 

 at B in the diagram. We were not able to observe this par- 

 ticular sub-peduncle any longer; but it would certainly liave 

 cone on circumnutating until the capsule was nejirly ripe (which 

 requires only a short time), and it would then have moved 

 upwards. 



The upward movement (C, Fig. 188) is effected in part by the 

 whole sub-peduncle rising in the same manner as it had pre- 

 ^^ously descended through epinasty — namely, at the joint where 

 united to the main peduncle. As this upward movement 

 occurred with plants kept in the dark and in whatever position 

 the main peduncle was fastened, it could not have been caused 

 by heliotropism or apogeotropism, but by hyponasty. Pesides 

 this movement at the joint, there is another o. a very difieront 

 kind, for the sub-peduncle becomes upwardly bent in the middle 

 part. If the sub-peduucle happens at the time to be inclined 

 much do\™wai-ds, the upward curvature is so great that the 

 whole forms a hook. The upper end beai-ing the capsule, thus 

 always places itself upright, and as this . ccurs in diu'kness, and 

 in whatever position the main peduncle may have been secured. 



