CHAP. I. RICINUS AND QUERCUS. 53 



were partially open and all opened in the course of the morning ; 

 but at 10.20 P.M. all four (not to mention nine others which 

 had been open in the morning and six others on another occa- 

 sion) were again completely closed. On the morning of the 

 29th they were open, but at night only one of the four was 

 closed, and this only partially; the three others had their 

 cotyledons much more raised than during the day. On the 

 night of the 30th the cotyledons of the four were only slightly 

 raised. 



Ricinus Borboniensis (Euphorbiacese). Seeds were purchased 

 under the above name probably a variety of the common castor- 

 oil plant. As soon as an arched hypocotyl had risen clear above 

 the ground, a filament was attached to the upper leg bearing the 

 cotyledons which were still buried beneath the surface, and the 

 movement of the bead was traced on a horizontal glass during 

 a period of 34 h. The lines traced were strongly zigzag, and 

 as the bead twice returned nearly parallel to its former course 

 in two different directions, there could be no doubt that the 

 arched hypocotyl circumnutated. At the close of the 34 h. 

 the upper part began to rise and straighten itself, dragging the 

 cotyledons out of the ground, so that the movements of the 

 bead could no longer be traced on the glass. 



Quercus (American sp.) (Cupuliferse). Acorns of an American 

 oak which had germinated at Kew were planted in a pot in 

 the greenhouse. This transplantation checked their growth; 

 but after a time one grew to a height of five inches, 

 measured to the tips of the small partially unfolded leaves on 

 the summit, and now looked vigorous. It consisted of six 

 very thin internodes of unequal lengths. Considering these 

 circumstances and the nature of the plant, we hardly expected 

 that it would circumnutate ; but the annexed figure (Fig. 40) 

 shows that it did so in a conspicuous manner, changing its 

 course many times and travelling in all directions during the 

 48 h. of observation. The figure seems to represent 5 or 6 

 irregular ovals or ellipses. The actual amount of movement 

 from side to side (excluding one great bend to the left) was 

 about *2 of an inch ; but this was difficult to estimate, as owing 

 to the rapid growth of the stem, the attached filament was 

 much further from the mark beneath at the close than at the 

 commencement of the observations. It deserves notice that the 

 pot was placed in a north-east room within a deep box, the top 

 of which was not at first covered up, so that the inside facing 



