(136 ) 



leaflets were pressed logetlier, as takes place in from 1 — Vj^^ hour 

 at the periodical passage from daj to night position. 



Idem, 4V2 p- ?'?• — The plant is cautiously transported from tlie 

 dark room into the full light without. 



Idem, 5 />. m. — Tlie three topmost j^oungest leaves have rjuite 

 recovered from the stimulation and are again fully expanded. Only 

 the two at the base are partly restored. 



Finally be it mentiojied that a simple "burning experiment", to 

 which anotlier Poinciania reyla was submitted, proved that the 

 iri'itation caused by burning one or two leaflets with a match was 

 not transmitted to the neighboiu-ing leaflets, notwithstanding this 

 species was very sensitive to mechanical stimulation (shaking;. 



Further it may be noticed that the non-artiticially irritated control 

 plant which was continually kept at a sheltered place, showed all 

 the day <|uite expanded lea\es. The determination of the species of 

 this biologically highly interesting plant 1 have verified and found 

 right. 



§ 'B. Calliandra spec. — A very young pot-i>lant grown 

 in the Buitenzorg Hortus under the garden-name of Calliandra 

 hamata (evidently erroneous for ////(^^/irt^ccf/Vi^ïA^ Hassk.) was subjected 

 to an irritation experiment on 5 February 7.30 a. m. by vigorously 

 tapping on the stem with a lead-|)encil. 



Within about 3 minutes the leaflets of the topmost (youngest) 

 leaf had closed, the other leaves only indistinctly reacting on the 

 stimulation, whereas in all the non-irritated plants all the leaves 

 (also the youngest) were then almost fully expanded. 



§ 4. C a 1 1 i a 11 d r a p o r I o r i c e n ^ i s Benth. — A shrul) 

 about 3 M. high with bipinnate leaves and narrow leaflets, grown 

 in the Hortus Bogor. in garden-bed XV. J. (A. XIV) Number 6, 

 under the said name found correct by me. 



When on 2 February at 574 p. m. 1 made an expenment with 

 it bv vigorous shaking, all the leaves were still in fully expanded 

 (lav position. Directly after the shaking the leaflets of the irritated 

 branches folded upwards and assumed closely pressed together the 

 nocturnal position ty|)ical for that species. Meanwhile the leaves of 

 the non-shaken branches remained expanded. When repeating this 

 experiment some days consecutively about \/j — 1 lioui- before sunset 

 1 obtained the same results. However, the experiment plant showed 

 in the forenoon at 7 o'clock, also wlien vigorously shaken, only 

 relatively feeble irritation movements, whilst in that case the nocturnal 



