204 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
(4) Structure of Organs. 
Flowers of Lemna,* * * § — Herr L. Vuyck describes tbe rarely seen 
flowers of Lemna. The stigma is funnel-shaped, and appears to have 
assumed the character of a nectary. This character and the spiny pol- 
len-grains seem to point to cross-pollination by means of insects. 
Anisophylly.f — Pursuing his investigations on this subject, Prof. J. 
Wiesner finds anisophylly a less common phenomenon with tropical 
trees than with those of temperate climates. Its object is to promote 
favourable conditions in the leaf for illumination. In large-leaved 
deciduous trees anisophylly is advantageous ; while in small-leaved 
plants with long internodes it is found to occur very rarely. In plants 
with small crowded leaves it is advantageous, since it increases the 
amount of light which reaches the lower leaves. Anisophylly is very 
seldom found in the leaves of evergreen trees. In the trifoliolate 
Gardenieas anisophylly seems to fulfil the purpose of increasing the 
extent of assimilating surface. Lateral anisophylly appears to be of no 
direct advantage to the plant. 
Antidr omy. :J — Mr. G. Macloskie gives further examples of this phe- 
nomenon in a variety of plants, and adduces illustrations of the law that 
tho original phyllotaxis may be frequently changed by the requirements 
of the plant in the way of light, or by other forces which act upon it 
during its growth. 
Opening and Closing of Stomates.§ — According to Dr. F. G. Kohl, 
the increase of turgor in the guard-cells of a stomate which causes it to 
open, is due to the action of a diastatic ferment. Closed stomates 
open when treated with a solution of diastase. The opening and closing 
is effected by changes of temperature or of light rather than of moisture. 
The author determined that it is the rays between B and C, and those 
at F in the blue, which are alone effective in this respect ; no motion 
took place in the yellow, green, violet, ultra-red, or ultra-violet. 
Hydathodes.j} — Herr G. Ilaberlandt gives further information re- 
specting these organs for the secretion and absorption of water, which 
are commonly met with in tropical vegetation. Unicellular hydathodes 
were observed only in two plants, but they attained in these examples a 
high degree of differentiation and adaptation. Their most common 
form is that of a capitate hair, consisting of three or more cells, in which 
the hydathodic functions are performed by the apical cell. A good 
example of this is furnished by Phaseolus multiflorus. When the leaf is 
fully developed, the hydathodes on the upper surface lose their property 
of excreting water, while the secretion continues unchecked on the under 
surface. That it is through the glandular hairs that the water is ex- 
creted was proved by experiments in destroying the function of these 
* Dodonsea, 1895, p. 60. See Bot. Centralbl., lxiv. (1895) p. 228. 
t SB. K. Akad. Wiss. Wien, ciii. 1894 (1895) pp. 624-64 (4 pis. and 3 figs.). 
Cf. this Journal, 1895, p. 448. 
X Bull. Torrey Bot. Club, xxii. (1895) pp. 466-70. Cf. this Journal, ante, p. 83. 
§ Ber. Yersamml. Deutsch. Naturf. u. Aerzte, 1895. See Bot. Centralbl., lxiv. 
(1895) p. 109. 
|1 SB. K. Akad. Wiss. Wien, ciii. 1894 (1895) pp. 489-538 (3 pis.). Cf. this 
Journal, 1895, p. 333. 
