Lives of Eminent Zoologists, from Aristotle to Linnaeus Part 17

XIV. RADIATae, with flowers composed of funnel-shaped florets at the centre, and flat ones at the circ.u.mference; as the daisy.

* * * _Dest.i.tute of flowers._

XV. APETALae, whose flowers have no true corolla; as the gra.s.ses.

XVI. APETALae, entirely dest.i.tute of flowers, but having leaves; as the ferns.

XVII. APETALae, without apparent flowers or fruit; as mosses.

_Division II._ TREES.

Without petals.

XVIII. APETALOUS _Trees_ or _Shrubs_, having their flowers dest.i.tute of corolla; as the box.

XIX. AMENTACEae, with the flowers disposed in catkins; as the oak.

With flowers of one petal.

XX. TREES with a regular or irregular corolla of one piece; as the lilac.

With regular flowers of several petals.

XXI. TREES or _Shrubs_ with rosaceous corolla; as the apple-tree.

With irregular flowers of several petals.

XXII. TREES or _Shrubs_ with papilionaceous corolla; as the laburnum.

Each of these cla.s.ses is subdivided into various sections or orders, founded upon modifications in the form of the corolla, the nature of the fruit, the figure of the leaves, &c. The sections contain a greater or less number of genera, under which are disposed all the species known to the author.

This cla.s.sification was of the greatest service to botanists; though it was, like every other method that had been proposed, defective in many respects. A great objection to it is, that it separates the herbaceous from the woody plants, thus tearing asunder the most natural connexions; nor is the form of the corolla always so determinate, that one can say whether it be bell-shaped, funnel-shaped, or salver-shaped,--a point which it is necessary to decide before the species can be made out.

Various changes were soon proposed, and new methods planned, so that the science was again falling into confusion, when Linnaeus published his system, which was presently adopted by many teachers, and long before his death was in general use.

He made the stamina and pistils the basis of his arrangement, which he was induced to do from the consideration of their great importance, as the parts most essential to fructification. These organs being a.n.a.logous to those distinguis.h.i.+ng the s.e.xes of animals, the Linnaean method is sometimes called the s.e.xual system. It consists of twenty-four cla.s.ses.

The first ten are determined by the number of the stamina.

Cla.s.s I. MONANDRIA, containing all plants of which the flowers have only one stamen; as the mare's tail.

II. DIANDRIA: two stamens; as the jasmine.

III. TRIANDRIA: three stamens; as wheat, oats, and gra.s.ses in general.

IV. TETRANDRIA: four stamens; as woodruff.

V. PENTANDRIA: five stamens; as the primrose.

VI. HEXANDRIA: six stamens; as the lily and tulip.

VII. HEPTANDRIA: seven stamens; as the horse-chestnut.

VIII. OCTANDRIA: eight stamens; as the heaths.

IX. ENNEANDRIA: nine stamens; as rhubarb.

X. DECANDRIA: ten stamens; as the pink.

In the next three cla.s.ses, the stamens exceed ten in number, but differ from each other in certain circ.u.mstances.

XI. DODECANDRIA: stamens from twelve to twenty; as in agrimony.

XII. ICOSANDRIA: twenty or more stamens, inserted upon the inner side of the calyx; as in the rose and apple.

XIII. POLYANDRIA: twenty or more stamens, inserted upon the receptacle or point of union of all the parts of the flower; as in the crowfoot and anemone.

The relative length of the stamens determines the next two cla.s.ses.

XIV. DIDYNAMIA: four-stamens, of which two are shorter; as in thyme and foxglove.

XV. TETRADYNAMIA: six stamens, of which two are shorter; as in cabbage and wallflower.

Three cla.s.ses are indicated by having the stamina connected by their filaments.

XVI. MONADELPHIA: stamens united by their filaments into a single body or set; as in mallows.

XVII. DIADELPHIA: stamens united into two distinct sets; as in fumitory.

XVIII. POLYADELPHIA: stamens united into three or more bundles; as in hyperic.u.m and cistus.

In the next cla.s.s, the stamens are united by their anthers.

XIX. SYNGENESIA: five stamens united by the anthers; as in the dandelion and violet.

In the twentieth, the pistil and stamen are united.

XX. GYNANDRIA: stamens united to the pistil; as in orchis.

The plants of all the above cla.s.ses have flowers furnished with both stamens and pistils; but in the next three the flowers are unis.e.xual.

XXI. MONOECIA: Flowers bearing stamens only, and flowers bearing pistils only, occurring on the same plant; as in the oak.

XXII. DIOECIA: stameniferous flowers on one, and pistilliferous flowers on another individual of the same species; as in willows.

XXIII. POLYGAMIA: Flowers bearing stamens and pistils, flowers bearing stamens only, and flowers bearing pistils only, all on the same individual, or on different individuals of the same species; as in the ash and pellitory.