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8UMMARY OF CURRENT RESEARCHES RELATING TO 
fore, to be not in the root, but in the axis of the inflorescence in Cocos , 
and in the upper part of the stem in Arenga. 
In three woody plants, natives of Java* * * § — Conocephalus azureus 
(Moraceae), Laportea crenulata (Urticaceae), and Bambusa sp. — Prof. 
Molisch finds an abundant bleeding from the stem, with very consider- 
able pressure, up to two atmospheres, even at the time when the plant 
is in full leaf. The temperature during (our) winter months is very 
high, day and night, with a constantly cloudy sky and daily rains. 
From incisions in the stem of climbing plants f he finds a copious 
flow of sap, both in the Tropics and in European species. The sap 
flows from the vessels, thus explaining their unusual size in climbing 
plants. The flow is a purely physical result of the exposure of the 
vessels on both sides, and shows that capillarity cannot play the part 
either of a water-retaining or of a water-raising force to any con- 
siderable extent. The phenomenon takes place, in Vitis and Clematis , 
in the height of summer, even in very dry weather and intense heat. 
Modification of Respiration by Changes in Temperature.J— M. 
W. Palladine states that (in Vicia Faba), if shoots are first of all placed 
either in a very high or a very low temperature, and then transferred 
to air of an ordinary temperature, the intensity of respiration is then 
greatly increased as compared with that of shoots not previously so 
exposed. The excess amounted to as much as 40-53 per cent. 
(3) Irritability. 
Motile Organs of Leaf-stalks.§ — Herr M. Moebius describes these 
structures especially in Bobinia , Rhus , and AJcebia, which he takes as 
three characteristic types. In Bobinia there is in the leaf-stalk a circle 
of distinct vascular bundles held together only by an outer ring of bast- 
fibres, with a broad pith and narrow cortex ; while in the cushion there 
is a very broad cortex and a closed xylem and phloem-cylinder, surrounded 
by a collenchyme ring round a narrow pith. In the cushions of Rhus 
and AJcebia the vascular bundles are distinct, while in Bobinia they are 
united ; in the two former genera the pith is more developed in the 
cushion than in the leaf-stalk ; in Bobinia much less developed. Virgilia 
lutea and Platanus orientalis have hollow cushions. Stomates are hardly 
ever found on the cushions. The aquiferous tissue in the cushions of 
the Marantaceae has a function in connection with their curvature. 
Rapidity of Circumnutation.|| — Elizabeth A. Simons finds the cir- 
cumnutation, in the plants examined, to be in most cases considerably 
more rapid than that stated by Darwin, and the optimum temperature to 
be as much as 12° higher, about 28° C. On dull cold days with a 
temperature of 15°-19°, the movements were found to be extremely 
slow. In Convolvulus sepium , two distinct types of stem were observed, — 
a rapidly circumnutating one, and a prostrate one showing extremely 
feeble movements. 
• Ann. Jard. Bot. Buitenzorg, 1898, 2 me Suppl., pp. 23-32. 
t S.B. k. k. Akad. Wiss. Wien, cvii. (1898) 18 pp. See Bot. Ztg., xlvii. (1899) 
2 te Abth., p. 132. J Comptes Rendus, cxxviii. (1899) pp. 1410-1. 
§ ‘ Ueb. Bewegungsorgane an Blattstielen,’ 1899 (1 pi.). See Bot. Centralbl., 
lxxviii. (1899) p. 342. 
|| Contrib. from the Bot. Laboratory, Univ. of Pennsylvania, ii. (1898) pp. 66-79. 
