84 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
a true example of the origin of species by means of natural selection. 
Instances are taken from the genera Gentiana and Euphrasia. 
Dimorphic Flowers in Gentianaceae.* — Herr E. Knoblauch finds 
the flowers in several genera of Gentianacem (chiefly Hockinia ) to be 
heterostylous. In the short-styled form the anthers are free, dorsifixed 
at the end of long filaments, and with scarcely a trace of connective. In 
the long-styled form the anthers are sessile or nearly so, and are united 
into a tube, and the anther-lobes are separated by a strongly developed 
connective, which is greatly elongated and slit at the apex in a swallow T - 
tail fashion. This is accompanied by a difference in the structure of the 
stigma, which is much more papillose in the short-styled form. The 
anthers in each form are nearly on a level with the stigma in the other 
form, and the dimorphism is obviously adapted to cross-fertilisation by 
insects. 
Flower and Fruit of Trapa.j — Sigg. G. Gibelli and F. Ferrero con- 
tinue their investigation of the anatomy and morphology of the flower 
and fruit of Trapa natans. During the development of the internal 
floral organs, the sepals and petals form a completely closed chamber 
into which no water can enter. The flower jn’esents the irregularity 
of the rudiments of the stamens making their appearance before those of 
the petals. Between the stamens and the ovary is a nectariferous 
cushion. The flowers are, however, entirely self-fertilised, pollination 
taking place within the cavity of the flower. About 12 hours after pol- 
lination, the flower reaches the surface of the water, owing to the carpo- 
tropic curvature of the peduncle, and remains there open for a short 
time. A detailed description is given of the anatomy of the ripe fruit, 
especially of its remarkable horns. 
Heterospermy of iEthionema.J — M. A. de Coincy states that several 
species of AEthionema (Cruciform) from Spain, in addition to heterocarpy, 
display also heterospermy. Some of the silicules are monospermous, 
while others, belonging to the same raceme, are oligospermous (usually 
containing only two seeds). The seeds in the monospermous silicules 
are quite smooth, while those in the oligospermous silicules are covered 
with small protuberances. 
Protection of Buds.§ — M. M. Raciborski describes in detail the 
various contrivances by which flower-buds are protected against injurious 
external influences such as drought, excessive rain-fall, excessive transpi- 
ration, the attacks of animals, &c. These need not occur in the flower 
itself, but may be found in bracts (spathe of Arum), leaves, hairs, emer- 
gences, in the excretion of protecting substances like mucilage, or in the 
position of the flower with respect to the axis. The special adaptations 
are discussed in the cases of maritime plants, xerophilous plants, epi- 
phytes, aquatic plants, tropical plants, and alpine plants. 
Distribution of Stomates.|| — According to M. L. Petit, the distribu- 
tion of the stomates on the two surfaces of the leaf is intimately con- 
* Ber. Deutsch. Bot. Gesell., xiii. (1895) pp. 289-98. 
f Malpighia, ix. (1895) pp. 379-437 (5 pis.). Cf. this Journal, 1892, p. 384 ; 
1894, p. 709. X Journ. de Bot. (Morot), ix. (1895) pp. 415-7. 
§ Flora, lxxxi. (1895) Erganz.-Bd., pp. 151-94 (30 figs.). 
|| ‘ De la distribution des stomates foliaires,’ Bordeaux, 1894, 3 pis. See Bull. 
Sue. Bot, Frauee, xlii. (1895), Rev. Bibl., p. 533. 
