A handbook of systematic botany

by Eugenius Warming

In his well known artificial system Linnæus divided the Vegetable Kingdom into twenty-four classes, based upon the number, relative position and union of the stamens with regard to each other, and also to the gynœceum.

Class	I.	Monandria.	Flowers with	1	stamen.
„	II.	Diandria.	„  „	2	stamens.
„	III.	Triandria.	„  „	3	„
„	IV.	Tetrandria.	„  „	4	„
„	V.	Pentandria.	„  „	5	„
„	VI.	Hexandria.	„  „	6	„
„	VII.	Heptandria.	„  „	7	„
„	VIII.	Octandria.	„  „	8	„
„	IX.	Enneandria.	„  „	9	„
„	X.	Decandria.	„  „	10	„
„	XI.	Dodecandria.	„  „	11 to 19 stamens.
„	XII.	Icosandria.	„  „	20 or more stamens inserted on the calyx.
„	XIII.	Polyandria.	„  „	20 or more stamens inserted on the receptacle.
„	XIV.	Didynamia.	Stamens didynamous.
„	XV.	Tetradynamia.	„  tetradynamous.
„	XVI.	Monadelphia.	Filaments united into 1 bundle.
„	XVII.	Diadelphia.	„   „  „ 2 bundles.
„	XVIII.	Polyadelphia.	„   „  „ several bundles.
„	XIX.	Syngenesia.	Anthers united together.
„	XX.	Gynandria.	Stamens and pistil united.
„	XXI.	Monœcia.	Flowers diclinous, ♂ and ♀ on the same plant.
„	XXII.	Diœcia.	„   „  ♂ and ♀ on different plants.
„	XXIII.	Polygamia.	♂-, ♀-, and ☿-flowers on the same plant.
„	XXIV.	Cryptogamia.	Flowerless plants (Ferns, Mosses, Algæ, Fungi).

These classes were further divided into orders, according to the number of styles, as Monogynia, flowers with 1 style; Digynia, with 2 styles, etc. Thus a Dock (Rumex), having 6 stamens and 3 styles, would be placed in Class VI., Hexandria, and Order III., Trigynia.

Class XIV. was divided into two orders. Order I., Gymnospermia, with seeds apparently naked, comprising the Labiatæ; and Order II., Angiospermia, with the seeds enclosed in a capsule (Bartsia, Rhinanthus).

Class XV. was divided into two orders: Order I., Siliculosa, fruit a silicula (Capsella); and Order II., Siliquosa, fruit a siliqua (Brassica).

Class XIX. was divided into Order I., Æqualis, all the flowers perfect (Sonchus); Order II., Superflua, flowers in the centre perfect, those at the circumference with pistils only (seemingly superfluous), e.g. Aster; Order III., Frustranea, flowers in the centre perfect, those at the circumference neuter, e.g. Centaurea.

“Fragments” of a natural system have also come down to us from Linnæus, who himself always recognised the imperfection of his artificial system.

System of Antoine Laurent de Jussieu (1789).

					Class
Acotyledones. Plants without cotyledons: Fungi, Ferns, Mosses, Algæ, Naiades					I.
Monoctyledones. Plants with one cotyledon:—
1. Stamens hypogynous					II.
2.  „  perigynous					III.
3.  „  epigynous					IV.
Dicotyledones. Plants with two cotyledons:—
1. Apetalæ		Stamens epigynous			V.
		„ perigynous			VI.
		„ hypogynous			VII.
2. Monopetalae		Corolla hypogynous			VIII.
		„ perigynous			IX.
		„ epigynous,		anthers connate	X.
				„ free	XI.
3. Polypetalæ		Stamens epigynous			XII.
		„ hypogynous			XIII.
		„ perigynous			XIV.
4. Diclines irregulares, male and female flowerson different plants, corolla generally absent.

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