. Cyclopedia of American horticulture : comprising suggestions for cultivation of horticultural plants, descriptions of the species of fruits, vegetables, flowers, and ornamental plants sold in the United States and Canada, together with geographical and biographical sketches. Gardening; Horticulture; Horticulture; Horticulture. 1388 POLLEN tlien, is to be found a reason for the beauty and special- ization of external wall. In entoiuophiious pollen the elliptical form of grain predominates, but the general shape is extremely various; and the plants producing such pollen are usually provided wi
. Cyclopedia of American horticulture : comprising suggestions for cultivation of horticultural plants, descriptions of the species of fruits, vegetables, flowers, and ornamental plants sold in the United States and Canada, together with geographical and biographical sketches. Gardening; Horticulture; Horticulture; Horticulture. 1388 POLLEN tlien, is to be found a reason for the beauty and special- ization of external wall. In entoiuophiious pollen the elliptical form of grain predominates, but the general shape is extremely various; and the plants producing such pollen are usually provided with beauty of dower, fragrance, or other insect attraction. In order that the pollen which has been trans- ported to the stigma may be effective, it must be healthy. Experiments have shown that weak, poorly nourished orchard trees often produce ineffective pollen. The nature of the season may also have great influence upon its character, continued rains. Oddly marked Browallia. Pollen grain of Schaueria flavicoma. Magnified. ng great losses by preventing the maturity of this product as well as by mechanical injury and by pre- cluding the winged carriers. Most plants have some special provision for the protection of the pollen against rain; that is, either by the closing of the flower under moist conditions, or by the location of the anthers in a sheltered tube, under projecting hairs, lobes, or other corolla appendages. The individual particles of pollen are in the form of delicate grains only readily visible in some quantity, as in powdery masses. At the time when they are set free, the grains are generally entirely distinct from one another, to be blown about by an accidental wind or carried by visiting insects. In some cases, however, the grains are bound together loosely or by means of delicate glutinous threads (Rhododendron); they may be closely U'lited into4's (heath family); or the whole tissue of an anther or its divisions may remain intact as pollinia (some orchids, mi
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Keywords: ., bookcentury1900, bookdecade1900, booksubjec, booksubjectgardening
