I. - Groups And Orders

Exogenous Plants or Dicotyledons.

Leaves with netted veins. Flowers usually quinary - the parts in fives, or quaternary - the parts in fours. Embryos with two (rarely more) cotyledons; hence dicotyledonous.

* Eriocaulon septangulare - Plate 24 B.

Thalamiflores: Polypetalous dichlamydeous plants, with the petals distinct (separable) from the calyx, and the stamens hypogynous; Orders numbered 1 to 7.

* Ovary apocarpous.

1. Ranunculaceous plants - herbs or climbing shrubs; stamens indefinite, inserted on the receptacle.

** Ovary syncarpous. † Placentas parietal (i.e. seeds attached to sides of carpels). Stamens six, united in two sets.

2. Fumariaceous plants - herbs; flowers very irregular, with two sepals and four petals.

‡‡ Stamens tetradynamous, distinct.

3. Cruciferous plants - herbs; flowers regular, of four sepals and four petals, arranged crosswise.

†† Placentas axile (i. e. seeds attached to axis of carpels). ‡ Flowers regular. § Sepals overlapping at the edge (imbricate). Ovary one-celled; stamens distinct.

4. Caryophyllaceous plants - herbs; leaves opposite, undivided, without stipules; flowers symmetrical, with 4-5 sepals and petals, and definite stamens.

Ovary many-celled,

(a) Stamens monadelphous,

5. Geraniaceous plants - herbs; flowers symmetrical, with five sepals and petals; carpels fixed around a persistent central axis.

(b) Stamens polyadelphous.

6. Hypericaceous plants - shrubs; leaves opposite, often dotted; sepals and petals five, stamens indefinite.

§§ Sepals parallel at the edge (valvate).

7. Malvaceous plants - herbs or shrubs; sepals and petals five, surrounded by an involucre of three or more bracts; stamens united by their filaments into a column around the pistil.

Calyciflores: Polypetalous dichlamydeous plants, with the petals usually distinct, and the stamens perigynous or epi-gynou3; Orders 8 to 12.

* Ovary superior, the calyx distinct from the carpels; (stamens perigynous).

8. Leguminous plants - shrubs or herbs; flowers very irregular, papilionaceous; stamens ten, all or nine of them united; ovary a legume or pod.

9. Crassulaceous plants - herbs, with succulent leaves; flowers regular, isomerous; carpels as many as the petals free.

** Ovary superior or half inferior, the calyx adhering more or less to the carpels; (stamensperigynous).

10. Saxifragaceous plants - herbs; flowers regular; stamens 5-10, separate.

*** Ovary inferior; (stamens epigynous).

11. Umbelliferous plants - herbs; fruit dry, of two carpels, separating from the axis.

12. Araliaceous plants - shrubs; fruit succulent, of more than two carpels, not separating.

Monopetals: Dichlamydeous plants, with the petals united (from the base more or less upwards) into a single piece; Orders 13 to 18.

* Stamens epigynous; (ovary inferior). † Stamens attached to the corolla, separate.

13. Dipsacaceous plants - herbs; flowers in compact heads or spikes; calyx surrounded by an involucre; stamens equalling in number the divisions of the corolla, the anthers free.

†† Stamens attached to the corolla, cohering by their anthers.

14. Composite plants - herbs; florets in heads; stamens equalling in number the divisions of the corolla, the anthers united into a ring around the style.

** Stamens hypogynous.

15. Ericaceous plants - shrubs; stamens as many or twice as many as the corolla lobes; anthers opening by two pores.

** Stamens perigynous. † Seeds attached to a free central placenta.

16. Primulaceous plants - herbs; stamens attached to the tube of the corolla, isomerous, opposite its lobes.

†† Seeds attached to a parietal placenta. ‡ Corolla regular.

17. Gentianaceous plants - herbs; stamens attached to the tube of the corolla, isomerous, alternating with its lobes.

‡‡ Corolla more or less irregular.

18. Labiate plants - herbs; corolla two-lipped; stamens didynaraous; ovary four-lobed, the lobes one-seeded.

Monochlamyds: Perianth single, consisting of a calyx only.

19. Chenopodiaceous plants - herbs; perianth small, inferior; carpels solitary, one-seeded.

Endogenous Plants or Monocotyledons.

Leaves with parallel veins. Flowers usually ternary - the parts in threes Embryos with one cotyledon, hence Mono-cotyledonous. This group includes Orders 20 to 24.

* Flowers perfect, with a petal-like whorled perianth. † Ovary inferior.

20. Orchidaceous plants - herbs; flowers six-leaved, irregular; stamens and style united into a central column.

†† Ovary superior.

21. Liliaceous plants - herbs; flowers six-leaved, the segments sometimes combined, regular; anthers turned inwards; style and ovaries consolidated.

22. Melanthaceous plants - herbs; flowers six-leaved, regular, long-tubed; anthers turned outwards; styles distinct; ovaries subterraneous in the flowering stage, separable.

** Flowers glumaceous, or formed of imbricated colourless scales, not truly whorled.

† Ovary 2-3-celled.

23. Eriocaulaceous plants - aquatic herbs, with spongy cellular leaves, and unisexual flowers in small crowded scaly heads.

†† Ovary one-celled.

24. Graminaceous plants - herbs, with grassy sheathing leaves, the leaves split on the side opposite the blade.