3. Stamina, fig. 38, the stamens, are situated withinside of the corolla, and are various in number in different flowers, from one to several hundreds. These are the essential organs of impregnation. A stamen usually consists of two parts,fiia mentum, the filament, and anthers, the an ther, the latter of which only is essential. Its most common shape is oblong, com posed of two cells or cavities, which burst by a lotvitudinal fissure on the outside. A more unusual structure is when the anther opens by pores towards the sum mit, as in the genus erica, or heath, of which such a profusion of beautiful species from the Cape of Good Hope enriches our green-houses. Some of their anthers, moreover, are furnished with variously formed and very elegant crests and spurs, which afford the botanist marks for dis criminating the species. The genus of the first, Pinits, has a jagged crest to its anthers, which serves also to distinguish some of the difficult species from each other. The situation of anthers upon their filaments is either pendicular or in cumbent. Some of the latter kind are versatile, being suspended by a fine thread, which admits of their being turn ed round a great number of times with out coming off. This may be seen to great advantage in the passion-flower, as likewise in the different species of lily. The cells of the anther are destined to contain the pollen, or dust. This appears to the naked eye like a fine powder; but when examined under the microscope, it is often found to have a very peculiar structure in different plants. It is dis charged chiefly in dry sunny weather, when either the coats of the anther, by bursting, scatter it abroad, which is often assisted by some elasticity of the filaments or other parts of the flower; or else it adheres to the rough bodies of insects, as they frequent the flowers in search of honey. Each grain of the pollen remains entire so long as it continues dry, being a membranous bag, so constructed as to burst when it meets with moisture, dis charging a fine elastic vapour, and this last is the effective part of the pollen. This is the general appearance of the substance we are describing ; but in the orchis family, the mirabilis, the asclepias, and some of its allies, the pollen is re markably different, consisting of glutin.• ous naked masses, sheathed inside, or concealed by the peculiar structure of the flowers; but scarcely, except in the mi., rabilis, lodged in a proper anther. The stamens are subject to be obliterated when the plant increases much by root ; they are metamorphosed into petals in what are called double flowers, as the ane mone and ranunculus, so much admired by curious florists.
4. Pistiila, the pistils, fig. 39, are also an essential part of a flower, standing within the circle formed by the stamens in the very centre of it ; at least, they are usually in the same flower with the sta mens. Sometimes they are placed in a different individual of the same species. Such are termed separated flowers. That furnished with stamens being called the male or barren blossom ; that with pistils the female or fertile one. Such as have both organs in the same individual have received the appellation of united or per fect flowers ; and here it may not be amiss to mention, that a flower furnished with both calyx and corolla is, in Linmean language, said to be complete ; when the corolla is wanting, incomplete; and when the corolla is present without the calyx, naked. When barren and fertile flowers
are borne by the same individual plant, such are named monoecions, as residing in the same house. If, on the other hand, they grow from two separate roots, they are dioecious. Some plants, besides these different kinds of flowers, bear others, in which the organs are associated. To these the term po ygamous has been applied. Each pistil consists of three parts, the germen, or rudiments of the future fruit or seed, which is of course essential ; the style, which is not universal ; and the stigma, which is necessarily so, being the part destined to receive the pollen, and being furnished with its own appro priate moisture, to make that substance explode. By this means the seeds within the germen are rendered fertile. In some plants the stigma has been ob served to be irritable, and in others to gape for the reception of the pollen. In general it remains vigorous no longer than till the pollen has had access to it. It is necessary for botanical purposes to observe, whether the germen be supe rior, that is, above the calyx and corolla, or inferior, below their insertion. Pistils as well as stamens are occasionally oblite rated or changed to petals.
Pericarfilum, the seed-vessel, for which some recent cryptogamic botanists have contrived a new term, sporangium, precisely of the same meaning, and al. together superfluous. The seed-vessel is formed of the germen enlarged, and is not an essential part ; for many plants have naked seeds, guarded only by the permanent parts of the flower. The wis dom of nature is very conspicuous in the contrivance of seed-vessels in general; some, which remain closed while they are moist, split open with elastic force when ripe and dry ; others serve for the food of animals. by whose means their seeds are transported to a distance ; others make their way into the ground, by some peculiar apparatus, near the spot where they are produced ; while others are wafted by the winds or transported by the waters to far distant situations. The fol lowing are the different kinds of seed vessels :-1 Capsule, a capsule, fig. 40, is dry and woody, coriaceous or membra nous, of one or more cells, opening and discharging its contents by valves or by pores. 2. Silique, a pod, fig. 41, is a long, dry, solitary, seed-vessel, of two valves, and divided into two cells by a li near partition, along each of whose edges the seeds are ranged ; of this the wall flower and stock are examples. Silicura, a pouch, is a small round pod. 3. Legit men, a legume, fig. 42, is the fruit of the pea kind, solitary, formed of two oblong valves, without any longitudinal partition, and having the seeds ranged along one of its margins only. 4. Drupa, fig. 43, a stone-fruit, like- the peach and cherry, has a fleshy undivided coat, containing a single hard stone or nut. 5. P mum, fig.
44, an apple, contains a capsule of seve. ral cells in a fleshy coat. 5. I Mem+, fig.
45, a berry, is fleshy, without valves, con taining one or more seeds lodged in pulp, as the goose-berry and currant. Some berries are compound, as the raspberry ; others are of a spurious kind, the pulp originating from some part not properly belonging to the fruit, as the calyx in the mulberry, and the receptacle in the strawberry. And, fig. 46, Strobilus, a cone, originates from a catkin, becomes harden ed, and enlarged into a compound seed vessel, as in the fir, birch, &c.