SEED. See Botany Index.

With respect to number, plants are either furnished with one seed, as sea-pink and bifton; two, as wood-roof and the umbelliferous plants; three, as spurge; four, as the lip-flowers of Tournefort and rough-leaved plants of Ray; or many, as ranunculus, anemone, and poppy.

The form of seeds is likewise extremely various, being either large or small, round, oval, heart-shaped, kidney-shaped, angular, prickly, rough, hairy, wrinkled, sleek or shining, black, white, or brown. Most seeds have only one cell or internal cavity; those of lesser burdock, valerian, lamb's lettuce, cornelian, cherry, and sebette, have two.

With respect to sublimate, seeds are either soft, membranaceous, or of a hard bony sublimate; as in gromwell, tamarind, and all the nuciferous plants.

In point of magnitude, seeds are either very large, as in the cocoa-nut; or very small, as in campanula, ammanna, rampions, and throat-wort.

With respect to situation, they are either dispersed promiscuously through the pulp (femina nidulante), as in water-lily; affixed to a future or joining of the valves of the seed-vessel, as in the cross-shaped and pen-bloom flowers; or placed upon a placenta or receptacle within the seed vessel, as in tobacco and thorn-apple.

Seeds are said to be naked (femina nuda) which are not contained in a cover or vellet; such as those of the lip and compound flowers, the umbelliferous and rough-leaved plants. Covered seeds (femina tecla) are contained in some vessel, whether of the capsule, pod, berry, apple, or cherry kind.

A simple seed is such as bears neither crown, wing, nor downy pappus; the varieties in seeds, arising from these circumstances, are particularly enumerated under their respective heads.

In assimilating the animal and vegetable kingdoms, Linnaeus denominates seeds the eggs of plants. The fecundity of plants is frequently marvellous; from a single plant or stalk of Indian Turkey wheat, are produced, in one summer, 2000 seeds; of eleocharis, 3000; of sunflower, 4000; of poppy, 32,000; of a spike of cat's tail, 10,000 and upwards; a single fruit, or seed-vessel, of tobacco, contains 1000 seeds; that of white poppy, 8000. Mr Ray relates, from experiments made by himself, that 1012 tobacco seeds are equal in weight to one grain; and that the weight of the whole quantum of seeds in a single tobacco plant, is such as must, according to the above proportion, determine their number to be 360,000. The same author estimates the annual produce of a single stalk of spleenwort to be upwards of one million of seeds.

The dissemination of plants respects the different methods or vehicles by which nature has contrived to diffuse their seeds for the purpose of increase. These by naturalists are generally reckoned four.

1. Rivers and running waters. 2. The wind. 3. Animals. 4. An elastic spring, peculiar to the seeds themselves.

1. The seeds which are carried along by rivers and torrents are frequently conveyed many hundreds of leagues from their native soil, and cast upon a very different climate, to which, however, by degrees they render themselves familiar.

2. Those which are carried by the wind, are either winged, as in fir-tree, trumpet-flower, tulip-tree, birch, arbor-vitae, meadow rue, and jessamine, and some umbelliferous plants; furnished with a pappus, or downy crown, as in valerian, poplar, reed, succulent-sallow-wort, cotton tree, and many of the compound flowers; placed placed within a winged calyx or seed-vessel, as in sycamore, sea-pink, dock, dioscorea, ash, maple, and elm-trees, logwood and woad; or lastly, contained within a swelled calyx or seed vessel, as in winter cherry, cucumbers, melilot, bladder-nut, fumitory, bladder-fennel, heart-seed, and chick-pea.

3. Many birds swallow the seeds of vanelloe, juniper, milletoe, oats, millet, and other grasses, and void them entire. Squirrels, rats, parrots, and other animals, suffer many of the seeds which they devour to escape, and thus in effect disseminate them. Moles, ants, earthworms, and other insects, by ploughing up the earth, admit a free passage to those seeds which have been scattered upon its surface. Again, some seeds attach themselves to animals, by means of crotchetts, hooks, or hairs, which are either affixed to the seeds themselves, as in hound's tongue, mouse-ear, vervain, carrot, bastard-parley, fanicle, water hemp-agrimony, arctopus and verbena; to their calyx, as in burdock, agrimony, rhoxia, small wild bugloss, dock, nettle, pellitory, and feed-wort; or to their fruit or seed-vessel, as in liquorice, enchanted's nightshade, crocus-wort, cleavers, French honey-fuckle, and arrow-headed grass.

4. The seeds which disperse themselves by an elastic force, have that force resident either in their calyx, as in oats, and the greater number of ferns; in their poppy, as in centaurea erupina; or in their capsule, as in geranium, herb-bennet, African spirea, fraxinella, horsetail, balsam, Malabar nut, cucumber, elaterium, and male balsam apple.

SEmen, in the animal economy. See Physiology and Anatomy Index.

SEMEN Sanicum, or Santonicum. See Artemisia.