Elements of botany and vegetable physiology, tr. from the fourth ed. by W. Macgillivray1831 |
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Elements of Botany and Vegetable Physiology, Tr. from the Fourth Ed. by W ... Achille Richard Previsualització no disponible - 2020 |
Elements of Botany and Vegetable Physiology, Tr. from the Fourth Ed. by W ... Achille Richard Previsualització no disponible - 2015 |
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alternate anthers axillar base belong Botany branches buds calyx calyx is monosepalous capsule carpels centre characters colour containing corolla corolla is monopetalous cotyledons cylindrical destitute of endosperm dicotyledonous disposed dissepiments distinct distinguished divided divisions embryo endocarp endosperm envelopes erect family is composed fecundation female flowers filaments five fleshy endosperm fluid four fruit furnished gemmule genera genus globular Gramineæ herbaceous herbaceous plants hermaphrodite hilum indehiscent inserted integument involucre irregular Juss Jussieu layers leaf leaves less limb Linnæus lobes male flowers medullary membranous monocotyledonous monopetalous corolla monospermous natural number of ovules opposite ovules pericarp petals petiole pistil placed pollen polypetalous polyspermous present Primulaceae proper integument racemes radicle rarely roots sarcocarp seeds sepals sessile sexual organs shrubs sometimes species spikes stamina stem stigma stipules style is simple summit surface terminated trees trophosperm tube tubercles tubular unilocular unisexual valves vegetables vessels woody
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Pàgina 147 - ... capable of performing the offices for which they were destined. Vegetables, on the contrary, are, at their first appearance, destitute of sexual organs, these not being developed by nature until the moment when they are to be employed for the purpose of fecundation. Another great dissimilarity between animals and vegetables is, that, in the former, the sexual organs are capable of performing the same function several times, and exist during the whole life of the individual which bears them ;...
Pàgina 193 - At other times, there are several pistils in the same flower ; as in the rose and ranunculus. The pistil, or pistils, when there are more than one, are often attached to a particular prolongation of the receptacle, to which the name of gynophorum is given, and which does not essentially belong to the pistil, but remains at the bottom of the flower when the pistil is detached.
Pàgina 189 - ... elementary a nature. The microscopic examination of the pollen was therefore a subject that required revision, and which could not fail to attract the attention of modern observers. The grains of the pollen are utricles of various forms, having no adhesion to the anther at the period of maturity, and containing a multitude of granules of extreme minuteness. The utricular membrane is sometimes smooth, sometimes marked with eminences or asperities. Sometimes it presents little flat surfaces or...
Pàgina 189 - Sometimes it presents little flat surfaces or prominences symmetrically arranged. When the pollen is perfectly smooth at its surface, it is not at the same time covered with any viscous coating, whereas the slightest eminences are indications of viscosity, The papilla-, mammillary eminences, Sec.
Pàgina 191 - It is composed of two membranes, the one external, thicker, and furnished with pores, aud sometimes more or less prominent appendages; the other internal, thin, transparent, and having no adhesion to the first. When submitted to the action of water, the inner membrane swells, the outer bursts at some part of its surface, and through the opening thus formed there issues a tubular prolongation, which forms a kind of bag, first observed by Needham.
Pàgina 194 - The ovary is generally free at the bottom of the flower ; in other words, its base corresponds to the point of the receptacle, into which are inserted the stamina and the floral envelopes, although it does not contract any adhesion with the calyx ; as is observed in the hyacinth, the lily, and tulip. Sometimes, however, the ovary is not met with in the bottom of the flower, but seems to be placed entirely beneath the insertion of the other parts ; in other words, it is united in every part of its...
Pàgina 145 - ... parts. In vegetables the same phenomena take place; the absorbed fluids pass through a certain course before they arrive at the leaves, in which the parts essential to nutrition are separated from those which are useless. Both animals and vegetables eject the substances which are unfit for their nutrition. One of the most striking differences between vegetables and animals consists in the circumstance, that the former are essentially nourished by inorganic substances, such as water, carbon, hydrogen...
Pàgina 147 - Both are provided with particular organs, which by their mutual influence concur in producing the most important functions of their life. Generation is the ultimate object for which nature has created the various organs of vegetables and animals. They exhibit the most perfect similarity in respect to this great function. From the action which, the male organ exercises upon the female organ, fecundation takes place, by which the embryo, yet in the rudimentary state, receives and preserves the vivifying...
Pàgina 193 - ... utricles, assume the form which they are to retain, and finally become grains of pollen. It will be seen that this mode of development is perfectly similar to that of the cellular tissue, which we described when treating of the elementary part of vegetables. The pistil is the female organ in plants. It almost invariably occupies the centre of the flower, and is composed of three parts, the ovary, the style, and the stigma.
Pàgina 147 - ... of their life. Generation is the ultimate object for which nature has created the various organs of vegetables and animals. They exhibit the most perfect similarity in respect to this great function. From the action which the male organ exercises upon the female organ, fecundation takes place, by which the embryo, yet in the rudimentary state, receives and preserves the vivifying principle of life. Here, however, we remark the modifications which nature has impressed upon these two great classes...