388 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
exist in the female flowers ; hut not with the result of producing fertile 
anthers, but rather of organs in which the fungus carries out its full 
development, and discharges its spores in precisely the same way as the 
anther does its pollen-grains. 
M. A. Mangin* * * § brings forward some new facts concerning parasitic 
castration, confirming the observations of M. Vuillemin on Lychnis 
dioica when attacked by Ustilago anther arum : — (1) The possibility of 
local infection (verified by M. Vuillemin for Lychnis dioica') must be 
admitted also for Euphorbia Cyparissias and E. verrucosa, attacked by 
Uromyces Pisi and V. scutellatus. (2) The parasite only increases in 
size the rudiments of organs which already exist. (3) The author states 
that, as far as he is aware, ovaries have not been observed in the male 
ustilaginized flowers of Lychnis vespertina and Muscari comosum, thus 
adding another proof to the fact that the parasite cannot bring into 
existence organs which are completely wanting. 
Function of Flowers in attracting Insects.f — Prof. T. Caruel 
doubts whether too much has not been taken for granted in the prevalent 
theory of the part played by the bright colour and sweet scent of flowers 
in attracting insects for the purpose of pollination ; seeing that, as far as 
we know, the visual and olfactory organs and perceptions of many 
animals are very different from our own. In particular he calls attention 
to the obviously different effect of odours on many animals from that which 
they produce on us ; to the eyes formed of facets and to the ocelli of 
insects ; and to their sensitiveness to the ultra-violet rays of the solar 
spectrum. 
Pollination of Autumn-flowering Plants. + — Dr. P. Knuth enume- 
rates the pollinating insects to a large number of species of flowering 
plants natives of Northern Germany. As a general rule the number of 
insects visiting a species is considerably less than that described by 
H. Muller ; this he attributes partly to the smaller number of insects 
in North Germany, but much more to the late period of the year at which 
the observations were made. In almost all cases insects with a wide 
distribution visit the same flowers in Northern and in Central Germany. 
Pollination of Aristolochia§ — Herr W. Burck recurs to the question 
of the self- or cross-pollination of this genus, the observations being 
made on A. barbata, eleyans, and ornithocephala. He asserts that the flowers 
arc not dichogamous, and confirms Van Tieghem’s statement that the 
style and stigma are abortive, and that the so-called stigmatic surface 
consists of the connectives which have coalesced by their sides into a 
cup, are provided on their margins with papillte, and have assumed 
the functions of a stigma. He states further that when flies enter the 
chamber formed by the lower part of the perianth, and become dusted 
with pollen, in their attempts to escape from the chamber they come 
again into contact with the woolly or glutinous hairs which clothe the 
walls of the chamber, and thus lose, before they pass to another flower, 
almost every grain of pollen. In A. barbata at least 600, and in 
* Comptes Eendus, cxiii. (1891) pp. 784-6. 
t Bull. Soc. Bot. Ital., i. (1892) pp. 108-11. 
t Bot. Centralbl., xlix. (1892) pp. 232-6, 263 7, 299-303, 360-7. 
§ Bot. Zt.g., 1. (1892) pp. 121-9, 137-44 (1 pi.). Of. this Journal, 1891. p. 216. 
