. Introduction to botany. Botany. i8o Introduction to Fig. 96. provide for the allurement of insects by offering them nectar and pollen for food, and for attracting their attention by means of odors and bright colors ; and at the same time they have had so to con- struct and arrange their parts that in- sects in securing food would necessarily carry the pollen from one flower to the stigma of another. 130. Allurement by Pollen. — Some , , flowers secrete no Pistillate and staminate flowers of Valhsneria sptrahs. On the right a staminate flower has floated against nCCtar bUt Olier an t
. Introduction to botany. Botany. i8o Introduction to Fig. 96. provide for the allurement of insects by offering them nectar and pollen for food, and for attracting their attention by means of odors and bright colors ; and at the same time they have had so to con- struct and arrange their parts that in- sects in securing food would necessarily carry the pollen from one flower to the stigma of another. 130. Allurement by Pollen. — Some , , flowers secrete no Pistillate and staminate flowers of Valhsneria sptrahs. On the right a staminate flower has floated against nCCtar bUt Olier an the pistillate flower and an anther is touching one abundance of DoUen of the stigmas. After Kerner. ^ Roses, Anemones, and poppies are of this sort. Flowers of this kind are more or less erect so that the pollen may not fall out, and the stamens are usually numerous. Insects which feed on the pollen of such flowers are certain to get their bodies dusted over, and in this way they carry the pollen from flower to flower. 131. Allurement by Nectar. — Nectar is the most com- mon and most important allurement for insects. It is a more or less watery solution of sugar, and of certain salts and aromatic substances, secreted by a special tissue known as the nectary, and expelled at the surface by transfusion through the epidermis, by breaking down of the tissues, or through a special opening of the nature of a stoma. The nectar either remains clinging to the surface of the nectary or it gathers in large drops and falls into a nectar recepta- cle provided for it, as in the case of violets, where horn-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Stevens, William Chase, 1861-. Boston, D. C. Heath & Co.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1902
