252 



CIRCUMNUTATION OF LEAVES. Chap. IV. 



qaite fully grown, produced by a lateral shoot, on a young tree 



3 feet in lieight, were obserred during 29 h. (July 31st), in the 



game manner as the leaves of the previous species. Both these 



leaves certainly circumnutafed, making 



Fig. 114. within the above period two, or two and 



a half, small, irregular ellipses. 



(26.) Cycas pcctinatu (Cycadese, Fam 

 224). — A young leaf, Hi inches in 

 length, of which the leaflets had only 

 recently become uncnrled, was observed 

 during 47 h. 30 m. The main petiole 

 was secured to a stick at the base of the 

 two terminal leaflets. To one of the 

 latter, 31 inches in length, a filament 

 was fixed ; the leaflet was much bowed 

 downward, but as the terminal part was 

 upturned, the filament projected almost 

 horizontally. The leaflet moved (see 

 Fig. 114) largely and periodically, for it 

 fell until about 7 p.m. and rose during 

 the night, falling again next morning 

 after 6.40 a.m. The descending lines 

 are in a marked manner zigzag, and so 

 probably would have been the ascending 

 lines, if they had been traced throughout 

 the night. 



Ofjcas pectinata : circura- 

 nutation of one of the 

 terminal leaflets, traced 

 from 8.30 A.M. June 

 22n(l to 8 A.M. June 

 24th. Apex of leaflet 

 7| inches from the ver- 

 tical gla-^s, so tracing 

 not greatly magniHed, 

 and here reduced to 

 one-third of original 

 scale; temp. 19°-21°C. 



CmcuMNUTATioN OF Leaves : 

 Monocotyledons. 



(27.) Carina Warscewiczii (CannaccsB, 

 Fam. 2). — The movements of a young 

 leaf, 8 inches in length and 3i in 

 breadth, produced by a vigorous young 

 plant, were observed during 45 h, 

 60 m., as shown in Fig. 115. The pot 

 was slided about an inch to the right on the morning of the 

 nth, as a single figure would have been too complicated; but 

 the two figures are continuous in time. The movement is 

 periodical, as the leaf descended from the early morning until 

 about 5 p M., and ascended dui-ing the rest of the evening and 



