298 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
apparatus ; but are not so decidedly cyanopliilous as the antipodals of 
Monocotyledons. 
With regard to the function of the antipodals, the authoress expresses 
her general concurrence with the conclusions of Westermaier.* 
Cross-pollination and Self-pollination. — Sig. L. Nicotra \ has in- 
vestigated the mode of pollination in a number of orchids belonging to 
the tribe Ophrydese, natives of Italy. Although the larger number are 
abundantly visited by insects, and show evident adaptations for cross- 
pollination ; in others, including the bee-orchis, the visits of insects are 
rare, and fertility appears to depend primarily on self-pollination. 
The mode of pollination of various species of Cucurbitaceae has been 
investigated by Dr. A. Brizi.J He finds them, as a rule, pollinated by 
the agency of Hymenoptera (Apidae) ; and the author supports the old 
view that they are attracted by the conspicuousness of the corolla, the 
flower affording a large amount of scentless nectar. The structure and 
position of the nectaries promotes the visits of these pollinating insects, 
while it hinders those of useless or injurious insects, such as ants. 
Dr. E. Ule § finds the structure of the organs in Aristolochia Clema- 
titis, as in A. Sipho , to point to the absolute necessity of cross-pollination. 
When the anthers are mature, the surface of the stigma has completely 
dried up and the stylar canal is closed. 
Relation between Insects and Flowers.||— Continuing his observa- 
tions on the agencies by which insects are attracted to flowers. Prof. 
F. Plateau now gives a large number made on Salvia horminum and 
Hydrangea opuloides, confirming his previous statement that they are 
not chiefly attracted by the sense of sight. Neither the coloured bracts 
in the former nor the conspicuous sterile flowers in the latter plant can 
be regarded as “ vexillary.” In both cases the pollinating insects make 
their way at once to the flowers which contain the honey without being 
visibly guided by the showy organs in either case ; while, if these are 
removed, it does not appear to make any material difference in the 
number of insects which visit the inflorescence. 
Cleistogamous Flowers of Bromeliaceae.1T — In 24 species of Brome- 
liaceae, natives of Brazil, mostly belonging to the genus Nidularium, 
<and many of them now described for the first time, Herr E. Ule finds 
Teistopetalous flowers. The author believes them to be in almost all 
cases pollinated by the agency of humming-birds. 
12) Nutrition and Growth (including- Germination, and Movements 
of Fluids). 
Action of the Rontgen Rays on Vegetation.** — The results of a 
further series of experiments have convinced Prof. G. F. Atkinson that 
the Rontgen rays do not in any way injure the growth or the sensitive- 
ness of plants. The observations were made on a variety of seedlings 
placed in a Crookes apparatus, on flowers, on bouillon-cultures of 
* Cf. this Journal, 1891, p. 760. 
f Bull. Soc. Bot. Ital., 1898, pp. 107-15. J Tom. cit., pp. 217-22. 
§ Ber. Deutsch. Bot. Ges., xvi. (1898) pp. 236-9. Cf. this Journal, 1898, p. 646. 
|| Mem. Soc. Zool. de France, xi. (1898) pp. 339-75 (4 figs.). Cf. this Journal. 
1898, p. 191. 1 Ber. Deutsch. Bot. Ges., xvi. (1898) pp. 346-62 (1 pi.). 
** Science, vii. (1898) pp. 7-13 (1 pi.). Cf. this Journal, 1898. p. 101. 
