SEE'BACII, MUtIE, Riga,.1835; daughter of an actor; was educated at Cologne for toe opera. She appeared in Vaudevilles at Nuremberg and Cassel; and a great success at Hamburg as Gretchen in Goethe's Faust, and as Cletrehen in Agmont. She performed at Hauover, 1856-65. Iu 1O6 she removed to Berlin with her husband, Albert Niemann, and in 1870 visited the United States.
MD, in phanerogamous plants, that part which may in some measure be regarded as corresponding to the perfectly developed impregnated,oram of animals, and wuich is the utmost effort made by the plant for the reproduction of its species. It is the per fectly developed ovule (q.v.). While one cell of the interior of the nucleus (see OvoLE) greatly enlarges, the other cells are forced back; the interior of the nucleus thus becomes a cavity (the embryo sac), and fecundation (q.v.) now taking place by means of the pollen, the primary cell is formed, which grows to form the embryo. As the fer-. tilized ovule is developed into the ripe seed, the foramen (see OVULE) or mecropyle closes completely; but its place is commonly marked in ripe seeds by a little In the ripe seed the integuments of the ovule, more fully developed, form the covering (sper modem); while the nac!eus is either entirely converted into the embryo (q.v.), or also into an inorganic cellular mass called the albumen (q.v.), which as, in an economical point of view, the most important part of many seeds, as of those of the cereal grasses.
i The embryo, which, with respect to the reproduction of the plant, is the most essential part of the seed, is developed to various degrees in different plants—which is also the case in dilferent animals. and even in those of the same class, as in mammalia; but in general, the radicle may be dietinguiehed in it—the beginning of the root or deseending axis of the new plant, and the plumule or gem•ule—the beginning of the stein or ascend ing axis, as well as the cotyledon or cotyledons, provided for the nourishment of the new • plant in its youngest stage. When the embryo is accompanied with albumen, it is sometimes completely inclosed in it; sometimes it lies at the side of the albumen; and sometimes it surrounds the albumen like a ring, or even completely. Sometimes, but , rarely, the embryo is not well developed in ripe seeds, so that its parts cannot be dis tinguished, as in the orchideo, in which it appears as a roundish or oval, uniform, little. cellular MASS. In germination the embryo breaks through the covering of the seed, and develops itself into the new plant.
Seeds are either sessile or stalked. The stalk is of various length, and is formed of the fanicalas or umbilical cord; the place at the base of the seed, by which it is affixed to the inside of the fruit, or to the end of the fanicalus, being called the umbilicus or hilum, When the seed is perfectly ripe, it has no further need of connection with the parent plant, and the fart!:aulu,s dries up, leaving the hilura a mere scar.
Besides being incloeed in a capsule, or in a succulent fruit, etc., the most essential parts of the seed have coveriege of their own, which are reckoned as belonging to the seed itself. Its general covering is called the sperm4derm (Gr. sperms, seed, derma, covering), which consists of an external membrane, the tests (Gr. shell) or episperm (Gr. epi, upon) and an internal membrane, the eadopleura (Gr. enlon, within, pleura. side). Sometimes there is within the episperm a fleshy layer, called the sarcosperm (Gr. sane, flesh). The aril (q.v.) is a comparatively rare additional covering.
The seeds of plumerogamous plants afford clihraaters which distidguish two great classes as mouocolyledquous and ifico:yledoaetts (see COTYLEDON). Very few plants have more than two cotyledons (seed lobes). It is the case, however, with some of the conif-• ems. Cryptogammie plants are also designated acotyledorous, as having no seed-lobes; and the name spore (q.v.) is distinctively given to their seeds.
Seeds retain their vitality very long; but the time seems to be very various with the seeds of different plants, and in different circumstances. The grains, or seeds of cereal grasses, are probably excelled in this respect by none; grains of maize found in the tombs of the incas have been made to vegetate; and also, it is said, grains of wheat taken from Egyptian mummies, although of this there is some donbt. After the great fire of London tu 1056. plants net previously common sprang up abundantly on the waste ground; certain plants previonsly unknown there are sure to appear after a fire in the American forests; and instances are constantly occurring of a deep trenching of land or a turning up of soil by railway or other operations, producing a crop of some kind of plant previously unknown or rare in the locality. Thus the writer of this nrticle has seen plante of the milk thistle appear on rubbish thrown out from the foundation of a house in Peeblesehire, where there was no other milk thistle in the neighborhood. And in Paisley Moss, in Renfrewshire, willows spring up in the ditches which arc cut for drainage, from the surface of the soil which underlies the moss or peat. It to conjecture how long the seeds, in such cases, may have retained their vitality.
Exposed to the air, however, seeds generally lose their vitality in a few years. Some Inds retain it much longer than others. Seeds which abound in fixed oil seem to lose it more quickly than others.
In conveying seeds from one part of the world to another, and through great diver sities of climate, it is desirable to have them as closely secured from the air as possible. But it has been found that of seeds brought from the botanic garden at Calcutta to, Scotland, round the cape of Good hope, with no other care tfian would be used in sending a parcel from a seed-shop to a neighboring garden, the greater part readily veg etated.