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 stamens hypogynous; it includes the Orders numbered 1 to 9.

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

1. Ranunculaeeous plants - herbs; stamens indefinite, usually numerous; anthers opening by two longitudinal clefts. [For the genera in the several groups, see page 28 and sequel.]

2. Berberidaceous plants - shrubs; stamens equal in number to the petals; anthers opening by recurved valves; carpel solitary.

** Carpels combined into an undivided (i.e. syncarpous) ovary which has two or more placentas.

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

‡ Stamens 6, tetradynamous (4 long and 2 short), distinct.

3. Cruciferous plants - herbs; corolla regular; petals four.

‡‡ Stamens 5, cohering in a ring around the ovary.

4. Violaceous plants - herbs; corolla irregular; petals five.

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

‡ Flowers symmetrical, i.e. the parts equal or proportional in number.

5. Caryophyllaceous plants - herbs; leaves undivided, without stipules; flowers regular; stamens definite.

6. Geraniaceous plants - herbs; leaves lobed, with stipules; flowers regular; styles and carpels combined around a long beaked axis.

7. Oxalidaceous plants - herbs; leaves in British species trifoliate; flowers regular; styles distinct.

‡‡ Flowers unsymmetrical, i. e. the parts neither equal nor proportional in number.

8. Aceraceous plants - trees; flowers regular; stamens distinct, definite; fruit consisting of two winged nuts.

9. Polygalaceous plants - herbs; flowers very irregular; stamens combined in two parcels.

Calyciflores: Polypetalous dichlamydeous plants with the petals usually distinct, and the stamens perigynous or epigy-nous; Orders 10 to 17.

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

10. Leguminous plants - herbs or shrubs; flowers very irregular, papilionaceous; the fruit a single carpel forming legume; stamens 10, all or 9 of them united.

11. Rosaceous plants - herbs or trees; flowers regular, rarely without petals; stamens indefinite; fruit one-seeded nuts or drupes, or follicles containing several seeds.

‡‡ Ovary inferior, the calyx adhering to the carpels.

12. Pomaceous plants - trees or shrubs, the fruit a pome.

13. Saxifragaceous plants - herbs, the fruit a capsule.

†† Carpels combined into an undivided ovary, which has more than one placenta.

‡ Ovary superior, the calyx distinct from the carpels.

14. Rhamnaceous plants - shrubs or trees; calyx-lobes four or or five, valvate; stamens opposite the petals.

15. Celastraceous plants - shrubs or trees; sepals four or live, imbricate; stamens alternate with the petals.

16. Portulacaceous plants - herbs; sepals two, imbricate; petals five, cohering at the base.

** Stamens epigynous.

17. Grossulariaceous plants - shrubs; flowers regular; ovary inferior, one-celled.

Monopetals: Dichlamydeous plants, with the petals united (from the base more or less upwards) into a single piece; Orders 18 to 30.

* Stamens hypogynous.

18. Ericaceous plants - shrubs; stamens free, equal to or twice as many as the lobes of the corolla, the anthers with an appendage, and opening by two pores.

** Stamens epigynous. † Stamens free, or distinct from the corolla.

19. Vacciniaceous plants - shrubs; stamens twice as many as the lobes of the corolla, the anthers opening by two pores.

† Stamens epipetalous, or affixed to the corolla. ‡ Carpels two- or more-celled.

20. Caprifoliaceous plants - shrubs; leaves opposite, without stipules; cells of the carpels many-seeded.

21. Galiaceous plants - herbs; leaves and leaf-like stipules forming radiate whorls around the square stem; cells of the carpels one-seeded.

‡‡ Carpels one-celled, one-seeded.

22. Valerianaceous plants - herbs; stamens fewer than the lobes of the corolla; anthers distinct.

23. Composite plants - herbs; stamens equalling in number the divisions of the corolla (i. e. isomerous); anthers united into a tube around the style (i. e. syngenesious).

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

24. Primulaceous plants - herbs; stamens equalling in number and opposite to the lobes of the corolla.

‡‡ Seeds attached to the sides of the carpels, or in the axial angle of the cells.

‡ Corolla regular or nearly so.

25. Apocynaceous plants - herbs; corolla contorted, the stamens isomerous, alternating with its lobes; ovaries two, distinct, cohering by their stigma.

26. Gentianaceous plants - herbs; stamens isomerous, alternating; ovary of 1-2 many-seeded cells; placentas parietal.

27. Boraginaceous plants - herbs; stamens isomerous, alternating; ovary four-lobed, with one ovule in each lobe.

‡‡ Corolla irregular.

28. Scrophulariaceous plants - green leafy herbs; ovary twocelled, the cells many-seeded; placentas axile.

29. Orobanchaceous plants - brown leafless herbs; ovary twocelled, the cells many-seeded; placentas parietal.

30. Labiate plants - green leafy herbs; flowers unsymmetrical; ovary four-lobed, with one ovule in each lobe.

Monochlamyds: Perianth single (i. e. consisting of a calyx only), or altogether wanting, and replaced by scaly bracts; Orders 31 to 40.

* Stamens and pistils combined in the same flower. † Stamens perigynous.

31. Thymelaeeous plants - shrubs; perianth coloured; carpels solitary, simple, becoming a berry or drupe.

32. Ulmaceous plants - trees; carpels blended into a twocelled ovary, becoming a membranaceous winged fruit.

‡‡ Stamens epigynous.

33. Aristolochiaceous plants - herbs; perianth coloured, superior; stamens inserted on the perianth.

** Flowers diclinous, i. e. the staminate and pistillate ones separate.

† Flowers having a calyx (i. e. monochlamydeous).

34. Elaeagnaceous plants - shrubs or small trees with scurfy leaves; carpels solitary, simple.

35. Euphorbiaceous plants - herbs or shrubs; carpels combined into a three-celled ovary, each cell containing one or two pendulous ovules.

36. Empetraceous plants - small shrubs; carpels combined into a 6-9-celled ovary, each cell containing one erect ovule.

†† Flowers naked, the calyx being replaced by scaly bracts (i.e. achlamydeous).

37. Amentaceous plants - trees or shrubs; carpels superior, naked.

38. Corylaceous plants - trees or shrubs; carpels inferior, seated in an involucre (cupuliferous).

39. Coniferous plants - trees or shrubs, with resinous acerose persistent leaves; ovules naked, becoming nuts enclosed within the hardened scales of a woody cone.

40. Taxaceous plants - trees or shrubs, with linear persistent leaves; ovules solitary, seated in a succulent cup.

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 the Orders numbered from 41 to 48.

* Flowers imperfect, naked i.e. without either perianth or glumes, or consisting of scales.

41. Araceous plants - herbs; inflorescence spathaceous i. e. from a spathe; flowers unisexual.

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

42. Iridaceous plants - herbs; perianth six-leaved; stamens three, distinct.

43. Amaryllidaceous plants - herbs; perianth six-leaved; stamens six, distinct.

44. Orchidaceous plants - herbs; perianth six-leaved irregular; stamens gynandrous (i. e. combined with the style). ft Ovary superior.

45. Liliaceous plants - herbs; perianth six-leaved (sometimes combined) regular.

*** Flowers perfect, with a dry calyx-like whorled perianth.

46. Juncaceous plants - herbs; perianth regular, six-leaved, brown.

**** Flowers glumaceous, i.e. formed of imbricated chaffy scales or glumes.

47. Cyperaceous plants - herbs; leaves with entire sheaths; bracts one to each flower.

48. Graminaceous plants - herbs; leaves with sheaths split on the side opposite the blades; bracts two to each flower.