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Taxonomy in Plants

miles, system, tay, division, plant, perth, seed, divided and loch

TAXONOMY IN PLANTS, derived from the Greek words rafts taxis, meaning arrangement, and nomos, law. Called sometimes taxology. It is the study of classi fication, especially from a biological aspect, and treating of the morphology of plant life. Ray (1703) divided the vegetable kingdom into two general classes: the Flowering and the Flower less, basing everything on one single character istic. Endlicher, a little over a century later, formed the plant world into two groups: Cormophyta and Thallophyta, but the division was very imperfect and overlapping. Later we find two groupings by Linnaeus under the titles: Phanerogamia and Cryptogamia, the former having flowers with stamens and pistils, the latter flowerless, seedless and propagated by spores. But the designation Cryptogamia, still retained by a few, their generative method being no longer cryptic (occult) or hidden from our present advanced knowledge. Thallophyta, still remaining in general use, no longer de scribes the class formerly considered by the ex pression. Thus with ever-increasing knowl edge of the life-workings of the plant realm bringing new facts we have had to change re peatedly the system in taxonomy to bring the additional facts into close relation. And so the system of Ray gave way to the Endlicher, the latter to the greatly improved system of Lin nzus (1735) with its 24 classes divided accord ing to the number and disposition of the stamens, with variant orders according to the number of styles or stigmas, etc. This method of systematization, proving its deficiencies ever more with a deeper investigation of plant nature, had to give way (1813) to the Candolle system, soon to be displaced by the Sachs method of classification with its seven divisions, Protophyta, Zygophyta, Oophyta, Carpophyta. Bryophyta, Pteridophyta, Phanerogamia. The Sachs system is much in use to this day, but the most recent classification of botan ists, based on the great advances brought about by microscopic and other researches into the plant structure, which keep disclosing weaknesses of the former system, are the following four main classifying divisions: (1) Thallophyta; (2) Bryophyta; (3) Pteridophyta; (4) Spermaphyta. The first three belong to the CrvPtograms, the latter to the Phoserogams. It is an improvement gen erally considered better suited to the enlarged range of the botanist's vision; but already criticism is creeping in and taxonomy in plants may be subjected soon authoritatively to a fur ther revision. • (1) Thallophyta. This division includes all of the four primary classes, the unicellular organic growth, having root, stem and leaf un defined. Under this head come the algae, fungi, bacteria and lichens. (See BOTANY).

(2) Bryophyta. These include the mosses and liverworts (hepatica), with distinct sexual organs in some, but in this division (as above stated) is the liverwort and other plants of the thallus type. (See BRYOPHYLLUM). (3) Pterido

phyla. These are often termed vascular cryptogains and include, chiefly, the ferns with their propagation by spores. Their stem, leaf and root are clearly defined. (See PHYTA). (4) Spermophyta or Phanerogams. These are lately being divided into angiosperms and gymnosperms and the angiosperms are sub divided into dicotyledons and monocotyledons. The Spernsophyta are the highest division of plants including those having true flowers and seeds. They are for the most part land plants, while many of the former divisions are aquatic. Their female cell (oospore) is fertilized in propagation and, protected by the ovule, be comes a seed, the seed formation being the characteristic of this group (termed also seed plants). Gymnosperms of this division have unisexual flowers, naked ovules with direct pollen fertilization, etc. (See GYMNOSPERM). Angiosperms have a chsed seed vessel (carpel) and other distinguishing characteristics. See PLANTS, CLASSIFICATION OF.

TAY, tä, (1) a river in Scotland, in the county of Perth, formed by two head-streams, the one issuing from the northeast end of Loch Tay and the other from Loch Lyon, a small lake on the borders of Argyllshire. The two streams unite about two miles northeast of Loch Tay, whence the river flows past Aber feldy, Dunkeld and Perth, at which last town it widens out into an estuary from one to three miles in breadth, becoming the northern bound ary of the county of Fife. The whole length is 120 miles and the area of basin 2,250 square miles. Vessels of 500 tons ascend to New burgh and those drawing nine feet to Perth. Its principal tributaries are the Tummel and Isla on the left and the Bran, Almond and Earn on the right. During the upper part of its course the Tay flows with a rapid current through a wild and highly romantic country and subsequently, after entering Strathmore, through the richest and finest valley in Scot land. In the summer of 1878 a railway bridge spanning the estuary of the Tay at Dundee was opened for traffic, but on 28 Dec. 1879 13 spans, crossing the navigable part of the river, were blown down in a violent storm, a passenger train, which then happened to be crossing, be ing precipitated at the same time into the river. A second bridge, over two miles long, with 85 spans and carrying two lines of rail, was opened in 1887. (2) A loch in the.county of Perth, a picturesque sheet of water 15 miles long and about one mile broad; receiving at its southwest end (near Killin) the Lochay and the Dochart and discharging at its northeast end at Kenmore by the Tay. It is 100 to 600 feet deep and is well supplied with fish. On its northwest shore rises Ben Lawers.