Mode Of Fertilization Research Articles

Fertilization of the Casuarinacæ

FEW recent articles in botanical literature can compare in interest and importance with that contributed by Dr. Melchior Treub to the tenth volume of the Annales du Jardin Botanique de Buitenzorg, “On the Casuarirtaceæ, and their Position in the Natural System.” The startling announcement is made of the occurrence of a mode of fertilization of the ovule essentially different from that which takes place in other flowering plants.

Scientific Serials

Journal of Botany, August to November.—The most important article in the recent numbers of this magazine is Mr. Charles Bailey's paper on the structure, &c., of Naias graminea, Delile, var. Delilei, Magnus, illustrated with four plates and many woodcuts. This interesting addition to the British flora—first found in 1883 in a canal in Lancashire—is a native of warmer climates, not being indigenous anywhere in Europe, and has probably been introduced with Egyptian cotton. Mr. Bailey gives an exhaustive account of the morphology of its various organs, and especially of its mode of fertilisation. The Naias belongs to a class of plants that may be called “protozoophi-lous,” the pollen being carried to the stigma by aquatic animals of low organisation, in this instance by the currents caused by the rotating cilia of species of Vorticellidæ—Most of the other articles in these numbers are of more limited interest, being topographical papers on the flowering plants or cryptogams of particular districts, or descriptions of new or little-known species.—Additional instalments are also given of Mr. J. G. Baker's synopsis of the genus Selaginella, which is still uncompleted, the species now described amounting to 180.

On the Fertilisation Of Certain Labiatæ

IN the early part of April of the present year I had an opportunity of watching somewhat closely the mode of fertilisation of some species of Labiatæ, on which some notes may be interesting. The species observed were the three most abundant of the early flowering representatives of the order, Lamium album, L. purpurettm, and Nepeta glechoma; the post of observation a bank covered by the three species growing completely intermixed, just outside a cottage-garden where were several hives of bees; the time occupied, several hours on three sunny mornings. The point which interested me most was the constancy with which the same species of insect confined its visits to the same species of flower, notwithstanding the close proximity in which the three were growing, this being perfectly in harmony with Mr. Traherne Moggridge's observations of a similar character respecting the visits of insects to fumitories and other flowers.

The Fertilisation of Fumariaceæ

Apropos of the interesting discussion on this subject which has appeared in your columns, I should much like to know whether any of your readers have observed the mode of fertilisation in Corydalis claviculata. Last summer I spent a considerable time in attempting to find this out, but without success. In every flower which I gathered in the mature state, I found the style broken off at the articulation immediately above the ovary, as if to prevent the possibility of fertilisation after a certain period. As the interior parts are completely concealed by the corolla, it was difficult to determine whether the separation had actually taken place on the flower, or was the result of the dissection, but I believe the former to be the case. In a large number of observations, extending over a considerable time, I never saw an insect visit the plant (this was in Westmoreland), though seeds were freely produced. Muller does not mention this species in his classical work on the subject, “Die Befruchtung der Blumen durch Insekten.”

Fertilisation of the Pansy.—Ground Ivy

Mr. Kitchener having been kind enough to send me the above letter, I may, perhaps, be allowed to add a few additional notes. Since writing the former paper I have had the opportunity of examining three other species of Viola, V. calcarata, elatior, and lactea, all of which present a remarkable contrast to V. tricolor in a very curious point of structure. In V. tricolor the stigma is brought into close contact with the lowest petal by a very peculiar “knee” in the style, the effect of which is so completely to close up the central cavity of the flower as to render it extremely difficult for any large insect to insert its proboscis into the spur. In all the three species above-named, which I believe to be fertilised by bees, the style is nearly straight, so as to leave a considerable gap between the stigma and lower petal, quite large enough for the insertion of the proboscis of a bee. In none of these is there the least indication of the black triangular streak on the style which I take to serve, in V. tricolor, the purpose of guiding the Thrips to the nectary. The ring of anthers is also perfectly closed, as described by Miss Dowson in the case of the Dog and Sweet Violet, there being no opening for the admission of the small insect, as in the pansy. A striking difference in the form of the stigma also favours the same conclusion as to the mode of fertilisation.

Balfour's Class-book of Botany

PROFESSOR BALFOUR'S “Class Book of Botany” is too well and favourably known to botanists, whether teachers or learners, to require any introduction to our readers. It is, as far as we know, the only work which a lecturer can take in his hand as a safe text-book for the whole of such a course as is required to prepare students for our university or medical examinations. Every branch of botany, structural and morphological, physiological, systematic, geographical, and palæontological, is treated in so exhaustive a manner as to leave little to be desired. The illustrations also form, when enlarged, the very best set of diagrams that a lecturer can have. After this, it may seem hypercritical to find any fault with the new edition. We cannot, however, but regret that the opportunity was not taken of rendering the book still more complete by bringing it down to our present state of knowledge. As stated on the title-page, the additions and corrections are entirely confined to the department of organography, and, as far as they go, are valuable. In particular, the treatment of the subjects of carpology, inflorescence, and phyllotaxis, is rendered much more complete. In other departments we have no such additions, and we miss any reference to the recent labours of Hildebrand, Parlatore, and others, following those of Darwin in the department of fertilisation; of King, Strasburger, and many others in the structure of the reproductive organs of Cryptogams, or to the remarkable observations of Prillieux, Rose, and Brongniart on the movements of chlorophyll. In the department of vegetable palæontology in particular, Unger, Schimper, Heer, Ettingshausen, Dawson, and Carruthers have rendered the science of 1854 scarcely recognisable in 1870; and yet we find not a word added, even to the first edition. The fault appears to be that the book was “stereotyped.” Scientific works ought never to be stereotyped. The author has evidently been exceedingly cramped in the insertion of new matter, and the correction of errors has been rendered impossible. Thus we find repeated the old account of the mode of fertilisation in Parnassia, which has been shown by both English and Continental botanists to be erroneous, and illustrated by a drawing which is quite incorrect. The work is one, however, which is indispensable to the class-room, and should be in the hands of every teacher. Balfour's Class-book of Botany; being an Introduction to the Study of the Vegetable Kingdom. With upwards of 1,800 illustrations. Third edition. (Edinburgh: A. and C. Black, 1870.)