SECTION II.
‘THE ELEMENTARY DIVISIONS OF A FLOWER, OR THE PARTS OF PRUCTIPICATION. — GENERAL REMARKS ON THE CALYX, COROLLA, NECTARY,STAMEN, PISTIL, SEED-VES~ SEL, SEED AND BECEPTACLE.—OBSERVATIONS ON THE VARIETY OF FLOWERS, AND ON INFLORESCENCE.
PARTS OF FRUCTIPICATION.
Having obtained a general knowledge of the preceeding parts, your attention must now be closely devoted to acquire a perfect comprehen- sion of the parts of fructification ; viz, the flower and the fruit,
OF THE FLOWER.
The parts which are considered necessary to form a perfect flower, are the calyz, the corolla, the stamen, the pistil and the receptacle. To these may be added the nectary, sced-vessel and seed,
THE CALYX.
The calyx is that part of the flower, often con- sisting of one or more green, or yellowish green
ELEMENTS OF BOTANY. 21
leaves placed at a small distance, or close to the corolla.
It is particularly conspicuous in the unexpanded fower bud of the Papaver Rheas, consisting of two green leaves, as represented in the #th figure, Also shown by the letter (@.) in the Ist fgare.
There are many kinds of calyces enumerated in general works; viz. the perianth, the fence, the catkin, the sheath, the glume, the veil and the curtain,
Perianth :—The perianth or flower-cup is the most common kind. It is generally green and sitaate immediately bélow the flower, so as to form a part of it.
Possessed by the Leontodon Taraxacum, Rosa Centifolia, Papaver Rhweas, &c. (F. 29)
Involucrum:—The fence or involucrum, is a species of calyx peculiar to umbelliferous plants.
Ifitis placed below the common receptacle, (a. a. F. 31.) as in the Coniam Maculatum, it is called a general involu- ‘crum ; and when attached to the smaller divisions, as also inthe hemlock, (b.b.) itis denominated a partial involuerum.
Amentum:—The catkin or amentum consists of a common cylindrical receptacle, beset with nu- merous scales, each of which is accompanied by ‘one or more stamens or pistils, so that the whole forms an aggregate flower.
22 ELEMENTS OF BOTANY,
{llustrated in the Salix Alba, Humolas Lupulus, and others. (F. 30.)
‘Sheath :—The sheath or spathe is that kind of calyx, which is situated more or less remote from the flower, and after constituting a covering to the infant bud, opens longitudinally.
‘This species of oalyx is present in the Colchicnm Au- tamnale, but represented by the 33d Figare as it occurs in the snow-drop.
Glume:—The glume or husk Is the peculiar . calyx of corn or grasses, constituted by valves, enclosing one or more florets.
‘Avena Sativa, Hordeum Distichon, Triticum Hybernum, &e. (F. 32.)
Veil :—The veil or calyptra is a kind of mem- braneous hood which is said to be the calyx of the mosses, covering their capsule or fructification, like an extinguisher on a candle.
Curtain:—The curtain or volva is the mem- branous covering of the fungus tribe, concealing their parts of fructification.
‘The intention of the calyx, with respect to the economy of the flower, is to protect the interior organs from atmospheric or casual inj
ELEMENTS OF BOTANY, 23
COROLLA. The corolla is the interior envelope of the flower, investing the central parts, but invested by the calyx. tis asually, in fact, the principal and most beautifal part
of the Bower, being that which is most coloured, and com- monly regarded as constitating the flower. (F. 1, b.)
If the corolla consists of more than one piece, the individual parts are technically called petals, or leaves of the flower.
The apparent use of the corolla is to protect the interior organs; and to increase or diminish the rays of heat for fecundation.
NECTARY.
With some flowers, there is a nectary or pe- culiar appendage, attached for the most part, to the corolla, secreting or containing a honied juice, though it is not necessary to a nectary, that honey should be present.
24 ELEMENTS OF BOTANY,
The horn-like process issuing from the base of the corolla of the Viola Odorata, isanectary. It assumes, however, a great variety of shapes and situations in different genera of plants. Tn the Aconitum Napelius, it is hooded ; in the Helleborus Niger, tubular; and in the Sinapis Alba, a gland.
STAMEN, ‘The stamens are very important organs of the flower. They are of a very slender fabric, and of a thread-shaped figure, situated, for the most part, immediately within the corolla. In the flowers of the Crocus Sativas, you will find three
stamens ; four in Rubia Tinctorum ; five in Daucus Carota ; and 80 on, with others.
Stamens are divided into two parts; viz. a filament and an anther. ‘The filament is the thread-shaped part (b.) in the 11th
Figure, and the head (a.) or afther, situated on the top of the lament.
‘The anther is the only essential part of the stamen. In this part there is a fine dust, called pollen or farina ; which, when the anther is ripe and bursts, is discharged upon the summit of the pistil, and impregnates the embryo seeds in the germen. .
ELEMENTS OF BOTANY. 25
PistiL.
The pistils are likewise small and column shaped organs, of the utmost importance to the economy of the ower. They occupy, almost in- variably, the centre of the flower, and are sur- rounded immediately by the stamens.
In the Crocus Sativus you will discover one pistil; in the Daucus Carota two; in the Linum Us imum five ; ‘and in the different Roses, many pistils.
Piatils consist of three parts; viz. the summit or stigma, the style, and the germen or ovary.
‘The stigma is denoted by the letter (a.) in the 12th Figure the style or middle portion by (b) ; and the germen at the inferior extremity, by the letter (c.)
‘The summit of the pistil is generally organ- ized to absorb the pollen of the stamen, the fe- cundating influence of which is communicated throngh a tube in the style, to the undeveloped seeds in the germen. When thia is accomplish- ing, the upper parts of the pistil fade away, but the germen, on the contrary, gradually in- creases in size, till it finally constitutes the seed- vessel,
26 ELEMENTS OF BOTANY.
SRED-VESSEL. Seed-vessels are of seven different kinds ; viz.
capsules, pods, legumes, drupes, pomes, berries and
cones,
Capsule :—The capsule is a dry, hollow, mem- branous seed-vessel, usually divided into valves, and opening naturally in some peculiar manner, according to the plant to which it belongs.
‘The Papaver Somniferum, Viola Odorata, Valeriana Offi- cin jcotiana Tabacum, and many others, have capsular seed-vessels.
Pod :—The pod is a species of seed-vessel, which consists of two valves or partitions, within which, the seeds are fixed alternately to each seam.
Ifthe pod is longer than it is broad (F. 39.), it is said to be a siligue, as in the Sinapis Nigra; but if it is broader than it is long (P. 40.), it is then termed, silicle, as in the Cochlearia Armoracia.
Legume :—The legume is likewise a seed- vessel of two valves, but in which the seeds are attached to one seam only.
‘The legume is met with in the Polygala Senega, Spartiam Scoparium, Glycyrrhiza Glabra, and others. (F. 38.)
Drupe:—The drupe is either of a pulpy nature,