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. This group includes the Thalamiflores, Calyciflores, Monopetals, and Monochlamyds.

Thalamiflores: Polypetalous dichlamydeous plants, with petals distinct (i. e. separable) from the calyx, and the stamens hypogynous; Orders numbered 1 to 18.

* Carpels more or less distinct (i. e. apocarpous), sometimes solitary with one lateral placenta.

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

** Carpels combined into an undivided (i.e. syncarpous) ovary.

† Seeds attached to the spongy dissepiments (i. e. placentas dissepimentalj.

2. Nymphaeaceous plants - aquatic herbs, with the carpels imbedded into the receptacle, or combined into a single many-celled ovary.

†† Seeds attached to the sides of the carpels (i. e. placentas parietal).

‡ Stamens indefinite.

3. Papaveraceous plants - herbs; flowers regular, with two sepals and four petals; stamens numerous.

4. Cistaceous plants - shrubs or herbs; flowers with three (or five) sepals and five regular petals; stamens numerous.

5. Resedaceous plants - herbs; flowers irregular, with four to six sepals, and several small unequal petals, some of which are divided; stamens few.

‡‡ Stamens definite. § Stamens tetradynamous (4 long, 2 short), distinct.

6. Cruciferous plants - herbs; flowers regular; sepals four; petals four, arranged crosswise.

§§ Stamens 6, united in two sets.

7. Fumariaceous plants - -herbs; flowers very irregular; sepals two; petals four.

§§§ Stamens 4 or 5, alternating with the petals, sometimes with accessory or additional ones opposite the petals.

8. Frankeniaceous plants - herbs; flowers regular, with four or five sepals and petals, and usually with accessory stamens.

9. Tamaricaceous plants - shrubs, with scale-like imbricating leaves; flowers regular, with four or five sepals and petals.

††† Seeds attached in the axis or centre of the carpels (i.e. placentas axile).

‡ Flowers regular (i. e. the parts equal as to size and form).

§ Sepals overlapping at the edge (i. e. imoricate).

|| Ovary one-celled.

10. Caryophyllaceous plants - herbs; leaves opposite, undivided, without stipules; flowers symmetrical, with four or five sepals and petals, and definite stamens.

11. Illeeebraceous plants - herbs; leaves opposite or alternate, furnished with stipules; flowers inconspicuous; calyx 3-5-lobed; petals 3-5, often rudimentary or wanting; stamens as many as the sepals, rarely fewer.

Ovary many-celled.

(a) Stamens distinct.

12. Elatinaceous plants - minute aquatic herbs; the symmetrical flowers with three to five sepals and petals, and as many or twice as many stamens.

(b) Stamens monadelphoiis.

13. Linaceous plants - herbs; leaves entire; flowers symmetrical, with five sepals and petals, and as many stamens united at the base into one parcel; carpels separating without leaving a central axis.

14. Geraniaceous plants - herbs; leaves divided; flowers symmetrical, with five sepals and petals, and five or ten stamens united into one parcel; carpels fixed around a persistent central axis.

(c) Stamens polyadelphous.

15. Hypericaceous plants - shrubs; leaves opposite, often dotted; flowers regular, with five sepals and petals; stamens indefinite, united below into 3-5 parcels.

§§ Sepals parallel at the edge (i. e. valvate).

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

17. Tiliaceous plants - trees; flowers attached to a leaf-like bract; sepals and petals five; stamens numerous, shortly cohering in several clusters.

‡‡ Flowers irregular.

18. Balsaminaceous plants - herbs; flowers of six pieces, very irregular, the sepals and petals all coloured, one of the sepals spurred; stamens five, the anthers cohering round the pistil.

Calyciflores: Polypetalous dichlamydeous plants, with the petals usually distinct, and the stamens perigynous or epigy-nous; Orders 19 to 27.

* Stamens perigynous. † Carpels more or less distinct, or single. ‡ Ovary superior, the calyx distinct from the carpels.

19. Leguminous plants - herbs or shrubs; flowers very irregular, papilionaceous; stamens 10, all or 9 of them united; ovary single, becoming a legume.

120. Rosaceous plants - herbs or shrubs; flowers regular, rarely without petals; stamens indefinite; fruit 1-2-seeded nuts or drupes, sometimes enclosed within the fleshy tube of the calyx, or follicles containing several seeds.

21. Crassulaceous plants - herbs, with succulent leaves; flowers regular; the sepals and petals usually five (sometimes 3-4 or 6-20), isomerous; carpels as many as the petals, free.

‡‡ Ovary superior or half-inferior, the calyx adhering more or less to the carpels.

22. Saxifragaceous plants - herbs; flowers regular; stamens definite; ovary syncarpous at the base, with a separate style for each carpel.

†† Carpels combined into an undivided ovary, with more than one placenta; (ovary superior).

23. Lythraceous plants - herbs; leaves opposite; sepals four, five, or more, united below into a tube; petals as many, inserted at the top of the calyx-tube; stamens as many or twice as many as the petals.

** Stamens epigynous; (ovary inferior). † Flowers not umbellate.

24. Onagraceous plants - herbs; leaves simple, usually opposite; flowers complete; sepals and petals four each, with four or eight stameus, or two each, with two stamens; seeds numerous.