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Botany. —1. Cross-section of fir-wood; 2, of linden. 3. Forms of leaves. 4. Inflorescence. 5,6 11. Root of corn. 12. Crocus-bulb. 13. Root of orchis conopsea. 14. Section of leaf-bud of alder-bud. 18. Bud of black poplar; 19, cross-section of same. 20. Section of leaf-bud of < 25. Bud of mountain-ash. 26. Ash-buds. 27. Naked buds of viburnum lantana. 2S. Develn] 33. Terminal buds of oak. 34. Rose-twig with bracts. 35. Leaf of orobus vermis with floral . Flowers. 7. Stamens. 8. Pistils, i). Pollen-grains. 10. Root or iris, dentaria, anil Baud-wort, grape-cherry. 15. Anacharis alsinastrum. 10. Thorn of sloe, with buds. 17. Cross-section of an >ak. 21. Alder-twig. 22. Maple-twig. 23. Cross-section of maple-bad. 24. Shoot of red-beech, pment of beech-buds. 29, 30. Shoots of red-beech. 31. Ash-twig, 32, same, longitudinal section. •leaves. 38. Jointed-sheath of polygonum hydroplper. 37. Sheath of grass-blade. 38, 39. Fruits.
talnment of the characters and limits of lowest subdivisions—orders, tribes, and genera. Great difficulty has Been found in arranging the orders in natural groups, although the attempt, very necessary to a complete system and a just exhibition of nature, has been very assiduously and perseveringly made by some of the greatest botanists. Endlicher recognized 7205 genera or plants in all; Hooker and Bentham's Genera Planlarvm reckons 7565.
BOTANY, Fossil, a study almost unknown until the beginning of the 19th c, but now of much importance in connection with paleontology. Besides the usual classification of plants there is generally recognized a sixtli class called protophytes, which embrace microscopic cryptogamous plants. These are diatoms and desmids. In botany, as in the animal kingdom, the simplest forms are reckoued the lowest; and, as in the history of animal life, we find that the lower forms of plants appeared first. This is proved by the fact that such forms are found in the oldest fossiliferous strata, the higher groups appearing only in later formations, the present flora being the most highly organized of any. It is known that plants preceded animals, for animals depend upon plants for food, while plants had power to assimilate inorganic substances. With regard to fossil specimens it must be remembered that as the continents came up out of the sea, and as all fossiliferous strata were deposited under water, therefore aquatic plants and animals were more likely to be preserved than animals and plants of the higher lands. In later geological ages the plants have been for the most part terrestrial, while the animals have been in far greater proportion aquatic. Animals also, ofteuer than plants, have some imperishable portions, and so the specimens of extinct animals are more nearly complete than are those of plants. Remains of marine fossil animals arc found in the drift deposited by the sea in successive invasions of the land; and such invasions have been followed by periods of immense duration in which the sea was far away from the invaded land. Within these indefinite periods no record was made, unless in the deep water of the sea or on the shores of other lands invaded duriug the interim. Therefore for any single country the records of marine life exist in a series of sections separated from each other by blanks covering enormous periods of time. The relations of extinct animals are, consequently, necessarily obscure. But the succession of land plants may have been unbroken, or nearly so; in any event, it is much nearer perfection than in the case of marine animals. It is therefore conceded that the records of plant life found in the seashore deposits and the lake beds of the earth will throw much light on the questions of evolution and the origin of species. An idea of the present state of knowledge in respect to fossil botany may l>e gathered from the following statement of some of the discoveries and deductions thus far made.
The protophytes are identified only with the recent deposits. Their absence from the Pahcozoic rocks may be explained by the fact that only such as secreted calcareous or silicious crusts or shells could under ordinary circumstances be preserved. The shields of diatoms arc more easily soluble than most forms of silica, aud perhaps some of the older beds of flint received their material from this source. Some of the small plants which secrete lime and are commonly called algae might be considered protophytes. These are and have been abundant in our seas, and may have contributed to the formation of the beds of fossiliferous limestone which make up so much of the Palaeozoic rocks. There are tertiary deposits made up of the shields of the diatoms at Monterey. Cal.. and near Richmond, Va. The desmids, which are non-silicious, are often found in flint of the cretaceous age, but diatoms under similar circumstances are rare.
The alga? (hydrophyta, or thallogerui) abound in all the oceans and seas, and are discovered in all strata from the lower Silurian upwards. But in the lower Silurian the only plants certainly traced are seaweeds. Plants found in the Cambrian rocks are described as of the genus eophyton. In the Trenton limestone are several species of algae. Seaweeds are common in the upper Silurian, the most important being a fossil of the Medina sandstone. In the same strata is the genus of fucolds called spirophyton, which runs through the Devonian and carboniferous systems, and is called the "cock'stail fucoid." In the upper Devonian and lower carboniferous strata is found a group of singular formation called dictophyton, and another equally remarkable, called uphantarda. In later formations alga: become numerous and gradually approach the forms of the present age. About 50 genera and 150 species have been described.
Lichens, which are so abundant now, are scarcely known in a fossil condition. But as they are exclusively terrestrial plants, they were less likely to be fossilized than the aquatic t/taUogens. It is considered that the lichens were much less abundant in the carboniferous age than now. The only known fossil species were found in amber and in the tertiary lignites. Those in amber arc of the same genera and for the most part of the same species with the lichens now common in America and Europe.
Probably because they are terrestrial, and most of them soft and easily perishable, fungi are almost as rare as lichens in the fossil strata. A considerable number of fungi have been described. They are almost all from the tertiary; but some species have been found in the coal-beds of Saxony, and a few have been found in amber. It is believed that some species described are not fungi, but shells, or fish scales.
Plants of the group anogeru, including hepatirm aud the mosses, now form a large part of our vegetation. With an expanse of development as wide as the earth, and va. Botany.
such vast abundance everywhere, it seems strange that no trace of anogen* has been found in the older geological formations. But in the tertiary formation both mosses and liverworts are found in considerable abundance, particularly in amber and lignites, and to the formation of the latter they appear to have contributed. Those preserved in amber served to show that nearly tlje same species are now growing in various parts of Europe. It is believed that the liverwort known as marchantia palydrotphia is the most widely distributed of living plants. The absence of anogens in the ancient flora shows that those plants, though low in the scale of plant life, arc of quite modern date.
There appears to be some reason to believe that the aerogens (ferns, equiseta, and lycopods) were the first forms of land vegetation on the earth. They are still represented, but are nowhere predominant, and in general they are insignificant among local living forms. They were formerly much more important, but hundreds of species have died out. Of the three orders united in this class, the lycopods seems to have been the earliest in point of time, and earliest in their subsequent development. They are now represented by various species of lycopodium, or ground-pine, most of which are small. The first lycopods are found in the upper Silurian rocks of Canada, England, etc. These were the forerunners of the large scaly-trunked trees of the carboniferous flora, in which flora they exceeded all other forms of vegetation. At the close of the palaeozoic age the lycopods seem to have almost disappeared. No specimen of the group has been found in the mesozoic or tertiary rocks. The ferns made their first appearance in the Devonian strata, and acquired greater importance than they have at the present time. In the middle and upper Devonian tree-ferns were numerous, and of greater dimension than any now living. Of the forms of the upper Devonian and carboniferous strata several hundred species have been described, and there are reasons to believe that they formed a much more highly organized, diversified, and beautiful group of plants than can be found in the fern-flora of to-day. In the mesozoic and tertiary rocks remains of fernaJiavc been found; but ferns reached their highest development in the carboniferous period. The equiseta, which now exist only in the form of scouring rushes, in the carboniferous and Devonian ages grew nearly to the size of forest trees, and in numbers were among the most important of the flora. In the mesozoic ages species of this genus existed, having trunks 6 in. in diameter. In the tertiary age the equiseta were larger than now, but were an unimportant portion of the flora of the time. The order of acrogens show a history in contrast with that of other cryptogami. They began very early in the earth's history, acquired a profuse development, and kept their standing through two geological ages. Then that standing was suddenly lost, and thenceforward their course has been downward, until from lordly trees they have degenerated to rushes, and lost all importance in botanical rank and in scientific consideration.
Quite the opposite are the facts in regard to the great group of endogent, among whicli are the grasses, palms, lilies, etc., including many of the loveliest forms of vegetable life. They include also the grains commonly called cereals, and are thus not only ornamental, but highly useful. They are of comparatively modern date. Few traces of them have been found in palaeozoic rocks, but they seem to have existed at least as flowering plants in the carboniferous age. In the triassic, Jurassic, and cretaceous formations they are represented by many genera. Palms appear in the cretaceous formation, the oldest representative being the fan-palm now growing in the southern United States. In the terliary era this flora rose to great importance, and remnants are found of many species of grasses, sedges, and lilies. It appears, therefore, that the endogens are of quite modern date, beginning in the mesozoic era, the inferior families coming in at a later period.
The exogens, now forming much the larger part of the vegetation of the globe, belong to the present or to the immediately preceding geological era. No actual traces ot angiosperms, the highest division of the exogens, have been found further back than the cretaceous rocks. Commencing in that era, they spread with great rapiditv, developed in remarkable force and variety, and before the close of the epoch they had"become the predominating type of vegetation, which gave the flora of the earth very nearly its present appearance. In the tertiary epoch many additions were made, comprising the most beautiful and useful of flowers and fruits, producing plants useful in supplying the animals then coming to development, and finally for supplying man. There is quite a different history for the inferior order of exogens, the gymnosperms. the conifers, and the cycads. The conifers seem to have been among the first of terrestrial plants, beginning far back in later epochs of the upper Silurian age. In the Devonian thev attained large size, as the petrified trunks found in middle Devonian rocks have proved. In the carboniferous age, conifers were abundant, producing forests much like the pine foresl3 of the present day. In the tertiary age, the conifers reached their highest development in the "mammoth trees," the "red wood," etc., of which' remarkable specimens are still to be seen in California. The pines and firs began in the cretaceous age, and have since been increasing in importance, at present constituting by far the larger part of the coniferous vegetation of the globe. Yews appeared in the tertiary period, podotarpua in the mesozoic, Inrix in the tertiary, arbor vita in the mesozoic, taxodium in the middle tertiary, the ghinko (which has now but a single representative) in the cretaceous. The cycads appeared in the carboniferous age, and in the mesozoic age became one of the