side (fig. 92), or the one may be erect and the other inverted, as in some species of Spiraea and Aesculus; or they may be placed one above another, each directed similarly, as is the case in ovaries containing a moderate or definite number of ovules. Thus, in the ovary of Leguminous plants (fig. 91), the ovules, o, are attached to the extended marginal placenta, one above the other, forming usually two parallel rows corresponding to each margin of the carpel. When the ovules are definite (i.e. are uniform, and can be counted), it is usual to find their attachment so constant as to afford good characters for classification. When the ovules are very numerous (indefinite), while at the same time the placenta is not much developed, their position exhibits great variation, some being directed upwards, others downwards, others transversely; and their form is altered by pressure into various polyhedral shapes. In such cases it frequently happens that some of the ovules are arrested in their development and become abortive.
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From Strasburger’s Lehrbuch der Botanik, by permission of Gustav Fischer. | |
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Fig. 112.—Ovary of Polygonum Convolvulus in longitudinal section during fertilization. (✕ 48.) | |
| fs, | Stalk-like base of ovary. |
| fu, | Funicle. |
| cha, | Chalaza. |
| nu, | Nucellus. |
| mi, | Micropyle. |
| ii, | inner, ie, outer integument. |
| e, | Embryo-sac. |
| ek, | Nucleus of embryo-sac. |
| ei, | Egg-apparatus. |
| an, | Antipodal cells. |
| g, | Style. |
| n, | Stigma. |
| p, | Pollen-grains. |
| ps, | Pollen-tubes. |
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| Fig. 113.—Vertical section of the ovule of the Scotch Fir (Pinus sylvestris) in May of the second year, showing the enlarged embryo-sac b, full of endosperm cells, and pollen-tubes c, penetrating the summit of the nucellus after the pollen has entered the large micropyle. |
When the pistil has reached a certain stage in growth it becomes ready for fertilization. Pollination having been effected, and the pollen-grain having reached the stigma in angiosperms, or the summit of the nucellus in gymnosperms, it is detained there, and the viscid secretion from the Fertilization. glands of the stigma in the former case, or from the nucellus in the latter, induce the protrusion of the intine as a pollen-tube through the pores of the grain. The pollen-tube or tubes pass down the canal (fig. 112), through the conducting tissue of the style when present, and reach the interior of the ovary in angiosperms, and then pass to the micropyle of the ovule, one pollen-tube going to each ovule. Sometimes the micropyle lies close to the base of the style, and then the pollen-tube enters it at once, but frequently it has to pass some distance into the ovary, being guided in its direction by various contrivances, as hairs, grooves, &c. In gymnosperms the pollen-grain resting on the apex of the nucellus sends out its pollen-tubes, which at once penetrate the nucellus (fig. 113). In angiosperms when the pollen-tube reaches the micropyle it passes down into the canal, and this portion of it increases considerably in size. Ultimately the apex of the tube comes in contact with the tip of the embryo-sac and perforates it. The male cells in the end of the pollen-tube are then transmitted to the embryo-sac and fertilization is effected. Consequent upon this, after a longer or shorter period, those changes commence in the embryo-sac which result in the formation of the embryo plant, the ovule also undergoing changes which convert it into the seed, and fit it for a protective covering, and a store of nutriment for the embryo. Nor are the effects of fertilization confined to the ovule; they extend to other parts of the plant. The ovary enlarges, and, with the seeds enclosed, constitutes the fruit, frequently incorporated with which are other parts of the flower, as receptacle, calyx, &c. In gymnosperms the pollen-tubes, having penetrated a certain distance down the tissue of the nucellus, are usually arrested in growth for a longer or shorter period, sometimes nearly a year. Fruit and seed are discussed in a separate article—Fruit. (A. B. R.)
FLOWERS, ARTIFICIAL. Imitations of natural flowers are
sometimes made for scientific purposes (as the collection of glass
flowers at Harvard University, which illustrates the flora of the
United States), but more often as articles of decoration and
ornament. A large variety of materials have been used in their
manufacture by different peoples at different times—painted
linen and shavings of stained horn by the Egyptians, gold and
silver by the Romans, rice-paper by the Chinese, silkworm
cocoons in Italy, the plumage of highly coloured birds in South
America, wax, small tinted shells, &c. At the beginning of the
18th century the French, who originally learnt the art from the
Italians, made great advances in the accuracy of their reproductions,
and towards the end of that century the Paris manufacturers
enjoyed a world-wide reputation. About the same
time the art was introduced into England by French refugees,
and soon afterwards it spread also to America. The industry
is now a highly specialized one and comprises a large number of
operations performed by separate hands. Four main processes
may be distinguished. The first consists of cutting up the various
fabrics and materials employed into shapes suitable for forming
the leaves, petals, &c.; this may be done by scissors, but more
often stamps are employed which will cut through a dozen or
more thicknesses at one blow. The veins of the leaves are next
impressed by means of a die, and the petals are given their
natural rounded forms by goffering irons of various shapes.
The next step is to assemble the petals and other parts of the
flower, which is built up from the centre outwards; and the
fourth is to mount the flower on a stalk formed of brass or iron
wire wrapped round with suitably coloured material, and to
fasten on the leaves required to complete the spray.
FLOYD, JOHN (1572–1649), English Jesuit, was born in Cambridgeshire in 1572. He entered the Society of Jesus when at Rome in 1592 and is also known as Daniel à Jesu, Hermannus Loemelius, and George White, the names under which he published a score of controversial treatises. He had considerable fame both as a preacher and teacher, and was frequently arrested in England. His last years were spent at Louvain and he died at St Omer on the 15th of September 1649. His brother Edward Floyd was impeached and sentenced by the Commons in 1621 for speaking disparagingly of the elector palatine.
FLOYD, JOHN BUCHANAN (1807–1863), American politician, was born at Blacksburg, Virginia, on the 1st of June 1807. He was the son of John Floyd (1770–1837), a representative in Congress from 1817 to 1829 and governor of Virginia from 1830 to 1834. After graduating at South Carolina College in 1826, the son practised law in his native state and at Helena, Arkansas, and in 1839 settled in Washington county, Virginia, which in 1847–1849 and again in 1853 he represented in the state legislature. Meanwhile, from 1849 to 1852, he was governor of Virginia, in which position he recommended to the legislature the enactment of a law laying an import tax on the products of such states as refused to surrender fugitive slaves owned by Virginia masters. In March 1857 he became secretary of war in President Buchanan’s cabinet, where his lack of administrative ability was soon apparent. In December 1860, on ascertaining that Floyd had honoured heavy drafts made by government contractors in anticipation of their earnings, the president requested his resignation. Several days later Floyd was indicted for malversation in office, but the indictment was overruled on technical grounds. There is no proof that he profited by these irregular transactions; in fact he went out of the office
