Page:The American Cyclopædia (1879) Volume XIII.djvu/601

 PLANT 585 for its end the production of seeds, and all its parts are subservient to that. Numerous as are the forms presented by flowers on every hand, they may all be referred to one simple plan. Instead of taking the simplest form of the flower for illustration, the plan of its structure may be best understood by the ex- amination of one of the more complete forms, one which has all the parts to be found in any flower. There are many flowers which might serve as a pattern or type, but there are reasons for using the one selected by Gray in his admirable " Lessons," one of the sedums or stonecrops. An examination of this flower shows, beginning from without, a series of five green, leafy parts, which together form the calyx ; the parts are sepals. Within these are five more delicate (and in this case white) leafy bodies, called petals, which form the corolla; and these two together are the floral envelopes. Immediately next to the co- rolla, toward the centre of the flower, is a series of (in this case 10) bodies, the stamens, quite unlike calyx and corolla, being slender threads with a knob at the apex of each ; and quite within all the other three series is a FIG. 13. 1. A complete Flower of Sedum. 2. Dissection showing receptacle and two members of each series, sepals, petals, stamens, and pistils. cluster of five green parts, the pistils. As the two outer series are termed the floral en- velopes, the inner two, the stamens and pis- tils, are the essential organs. All of these, in the order here named, are placed upon the end of the flower stalk, which often has an enlargement to hold them, called the recepta- cle. A longitudinal section through the flower would show each series placed one above the other upon the receptacle ; or their position may be made plainer by an illustration giv- ing two of each series detached, but in their relative positions. The calyx is generally green and leaf -like in texture, though in some plants, as the fuchsia, it is colored, a term used in botany for any other color than green. The corolla is of a more delicate texture and is very rarely green, but is usually the most showy part of the flower. The stamens have two distinct parts, the stalk or filament, and the anther or knob at the top ; the anther is the important part of the stamen, as the fila- ment may be short or wanting ; it usually con- sists of two cells which open longitudinally to discharge the pollen, though in other plants there are various other ways for its escape. The pollen, or male element, consists of minute FIG. 14. 1. Stamen: a, fila- ment ; 6, anther discharging pollen. 2. Pistil and cross section. 3. Pistil cut length- wise: a, ovary; &, style; c, stigma; d, ovules. grains, usually rounded, and is generally yel- low. The pistil consists of three parts : the lower distended portion (often more distinct than in this plant), the ovary ; an elon- gated portion, the style ; and at the apex a part without epidermis, and usu- ally viscid, the stig- ma. The ovary, be- ing cut open longi- tudinally, is found to contain (in this case) numerous small pulpy bodies, the ovules. The influ- ence of the pollen falling upon the stig- ma causes a growth to take place within these ovules, which results in the forma- tion of seed. Such being the parts of the flower, and such their general func- tions (to be more fully mentioned fur- ther on), it remains to point out the leading modifications these parts undergo to produce the great diversity flowers everywhere present. The pedicel or flower stalk and the floral leaves or bracts, not strictly belonging to the flower, are placed so near it that they may affect its general ap- pearance, or that of the flower cluster taken as a whole ; in the Venetian sumach or smoke tree, the flowers are very small, but the pedi- cels, especially those which bear no flowers, are thickly clothed with hairs and increase in size, so that the conspicuous part of the inflo- rescence is these plumed stalks. The bract, besides differing in size and form from ordina- ry leaves, in many plants becomes petal-like and conspicuous; in the linden or basswood, each peduncle, or common flower stalk, has at its base a long ribbon-like bract attached for about half its length to the peduncle, and of a pale straw color which makes it nearly as con- spicuous as the flowers. (See LINDEN.) In some sages, especially salma splendens, the bracts are larger than and quite as brilliant as the flowers themselves, and much of the showy character of the plant depends upon them; while in euphorbia pulcherrima (best known as Poimettia) the plant is cultivated solely for its gorgeous scarlet bracts, which surround a clus- ter of inconspicuous flowers The appearance of a whorl of bracts as an involucre was noted in describing the umbel. Flowers of the large family of composite have involucres often of many series of closely overlapping bracts (e. g., thistles and sunflowers), in some cases leafy, and in others so nnlike leaves as to be reduced to mere papery scales. The ter