ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
409 
by different kinds of pollen produces no mixed types, but that each kind 
of pollen, on tbe contrary, exercises its own effects entirely independently 
of tbe others. He confirms, on the other hand, Kolreuter’s statement 
that, when different kinds of pollen act at the same time, on the same 
stigma, forms result which present intermediate characteristics ; half- 
bastards or “ tinctures ” when a small quantity of a plant’s own pollen 
and a large quantity of a foreign pollen are used. 
Pollination of Cyclamen.* — Herr F. Hildebrand describes a peculiar 
contrivance for aiding cross-pollination in the spring-flowering species 
of Cyclamen ( C . persicum , coum, ibericum, &c. When the pollen first 
escapes from the terminal orifice of the anther, the pollen-grains adhere 
together in lumps by an oily secretion, which prevents their falling on 
to the stigma in the same flower. The first portion of the pollen 
leaves the anther in this condition, and is abundantly carried away by the 
numerous visiting insects. The oily secretion, however, rapidly dries up ; 
and when the later portion of the pollen falls from the anther — at which 
time insects are no longer visiting the flowers — the grains are dry, and 
are readily carried by the wind to other flowers. The autumn-flowering 
species of Cyclamen ( C . grsecum , neapolitanum, africanum) appear not to 
be visited by insects. In most species of Cyclamen (e.g. C. persicum) the 
stigma ends abruptly in a flat surface, which is not papillose or hairy, 
but has a deep depression in which the pollen collects. In C. ibericum and 
coum , on the other hand, the stigma is provided with a tuft of papillae, 
from which the stigmatic fluid secretes that detains the pollen-grains. 
Cross-Pollination and Self-Pollination.— Mr. C. Robertson’s f latest 
contribution to this subject treats of the adaptations for pollination 
and the insect-visitors of a number of species belonging to different 
natural orders growing in Illinois. 
JDr. P. Knuth X has investigated the pollination phenomena of the 
flora of Heligoland. Out of 174 species of flowering plants, 50, or 
about 30 per cent., are anemophilous ; Zostera marina is hydrophilous ; 
Lemna trisulca does not flower. The pollinating insects are chiefly 
flies ; there are a few Lepidoptera, but no honey-bees or humble-bees. 
The same writer § describes the mode of pollination in Matthiola 
incana and Lunaria biennis. In both species the two shorter stamens 
seem designed for cross-pollination by insects, the four longer ones for 
self-pollination when cross-pollination fails. Both species are visited 
by butterflies : — the former by Vanessa TJriicse ; the latter both by the 
small tortoise-shell and by Pieris Brassicse , also by a bee, Anthophora 
pilipes. In this case also, a bee, Andrena Gwynana , and a hover-fly, 
Syritta pipiens, are efficient in self-pollination. In both species the 
male and female organs mature synchronously. 
(2) Nutrition and Growth (including- Germination, and Movements 
of Fluids). 
Laws of Growth. || — From observations made on a variety of plants, 
Sig. L. Montemartini concludes that the activity of the growing point 
* Ber. Deutscli. Bot. Gesell., xv. (1897) pp. 292-8(4 figs.). 
t Trans. Acad. Sci. St. Louis, vii. (1893) pp. 151-79. i 
X Bot. Jaarb. Gent, 1896, 47 pp. and 1 pi. See Bot. Centralbl.,lxx. (1897) p. 274. 
§ Bot. Centralbl., Ixx. (1897) pp. 337-40 (6 figs.). 
U Atti 1st. Bet. r. Univ. Pavia, v. (1896). See Bot. Centralbl., Ixx. (1897) p. 276. 
