ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
629 
which the pollination is effected. The present instalments refer to 
species belonging to the natural orders Nymphaeaceee, Cruciferse, Gera- 
niacege, Balsamineae, Celastraceae, and Papilionaceae. 
Dichogamy.* — Dr. A. Kernel* v. Marilaun describes the various 
degrees of perfect and imperfect proterandry, and of perfect and im- 
perfect proterogyny in plants, and the part which imperfect dichogamy 
(proterandry or proterogyny) plays in the production of hybrids in 
nature. 
Conversion of a bisexual into a dioecious Plant.f — M. A. Giard 
describes the finding of several plants of Pulicaria dysenterica , in which 
all the ligulate were replaced by tubular flowers. By destroying all 
normal plants in the vicinity, he succeeded in perpetuating this anomalous 
form from generation to generation for ten years ; thus transforming, 
by artificial selection, a gyno-monoecious into a dioecious Composite. 
Strengthening of the Sexuality of a Hybrid 4 — M. L. Trabut de- 
scribes an Ophrys intermediate between 0 . tenthredinifera and 0 . scolopax 
which showed a transformation in some of the flowers of two petals into 
two stamens, or, in other words, a strengthening of the sexuality — which 
is the reverse of what is generally found in most hybrids. 
Fertilization of Arum and Dracunculus.§ — According to Prof. G. 
Arcangeli, the fertilization of the flower of Dracunculus vulgaris ( Arum 
Dracunculus) is effected mainly by necrophilous Coleoptera, attracted by 
the powerful odour which exhales from the open spathe, and chiefly by 
Saprinus nitidulus , the species next in efficiency being S. subnitidus, 
Dermestes undulatus, and D. Frischii. 
Prof. F. Delpino,|| on the other hand, adduces arguments in favour of 
the view that these Coleoptera-play but a subordinate part in the 
pollination, the chief agents being carnivorous flies, principally Calli- 
phora vomitoria and Sarcophaga carnaria. 
Prof. Arcangeli f replies to the observations of Delpino, classing 
Dracunculus among necrocoleopterophilous plants, along with Rafflesia , 
Amorphophallus, Hydnora abyssinica , and others. 
The flowers of Arum pictum are, according to Sig. U. Martelli, ** 
strongly proterogynous, and exhale, when open, a most powerful odour 
of human excrement, which attracts insects belonging to various orders 
to perform the function of pollination. 
Fertilization of Brassica oleracea.f Dr. E. Cobelli enumerates as 
many as fifty species of Apidee, which he has observed visiting the 
flowers of different varieties of the cabbage, and which may possibly 
take part in the pollination of the stigma. 
* Oesterr. Bot. Zeitschr., xl. (1890) p. 1-7. 
t Bull. Scient. Fiance et Belgique, 1889, pp. 53-75 (1 pi.). See Biol. Centralbl., 
x. (1890) p. 19. 
X Comptes Rendus, cx. (1890) p. 480. 
§ Nuov. Giorn. Bot. Ital., xxii. (1890) pp. 52-7. Cf. this Journal, 1883, p. 382. 
|| Malpighia, iii. (1890) pp. 385-95. 
t T. c., pp. 492-507. 
** Nuov. Giorn. Bot. Ital., xxii. (1890) pp. 129-32. 
ft Yerhandl. K. Iv. Zool. Bot. Gesell. Wien, xl. (1890) Abhandl., pp. 161-4 
1890. 2 Y 
