Ocotea, Aubl.

Werff, Henk Van Der, 2013, A revision of the genus Ocotea Aubl. (Lauraceae) in Madagascar and the Comoro Islands, Adansonia (3) 35 (2), pp. 235-279 : 237-241

KEY TO THE SPECIES OF OCOTEA AUBL. IN MADAGASCAR AND THE COMORO ISLANDS

The choice offered in couplet 26, reticulation raised or immersed on the upper leaf surface, is sometimes difficult to make. Therefore, I have added an alternative key from couplet 26 onwards that avoids the venation character and instead emphasizes the presence or absence of pubescence at the inner surface of the receptacle.

1. Plants from the Comoro Islands .............................................. O. comoriensis Kosterm.

— Plants from Madagascar ............................................................................................. 2

2. Leaves with domatia (slits, pockets or tufts of hairs) in the axils of the lowermost lateral veins ................................................................................................................................... 3

— Leaves without domatia ............................................................................................ 16

3. Leaves opposite or subopposite ................................................................................... 4

— Leaves alternate .......................................................................................................... 5

4. Domatia consisting of tufts of reddish hairs; indument on lower leaf surface consisting of erect, straight or curled hairs, individual hairs clearly visible under a microscope ................ ................................................................................ O. thouvenotii (Danguy) Kosterm.

— Domatia consisting of shallow pockets or deep pockets with a slit-like opening, never fringed by reddish hairs; lower leaf surface glabrous or with minute, ± appressed hairs, individual hairs scarcely visible ............................................... O. corethroides Kosterm.

5. Lower leaf surface pubescent ...................................................................................... 6

— Lower leaf surface glabrous (some hairs may be present along the midrib) .................. 8

6. Inflorescences 2-6 cm long; leaves to 9 cm long ......... O. ivohibensis van der Werff , sp. nov.

— Inflorescences 5-12 cm long or more; leaves 9-19 cm long ......................................... 7

7. Leaves pinnately veined; indument on leaves and twigs reddish (castaneous) ...................... ..................................................................................................... O. longipes Kosterm.

— Leaves tripliveined; indument on leaves and twigs pale yellow or gray .. O. grayi van der Werff

8. Domatia a depression, sometimes completely covered by hairs or with a slit-like opening, this covered by hairs ................................................................................................... 9

— Domatia consisting of cavities with a narrow opening, not completely covered by hairs (the opening may have a fringe of hairs) ................................................................... 11

9. Inflorescences 8-12 cm long (Ft. Dauphin) ..................... O. malcomberi van der Werff

— Inflorescences to 6 cm long ...................................................................................... 10

10. Flowers densely pubescent; midrib and lateral veins immersed on upper surface; domatia with a fringe of white hairs ............................................................ O. trichantha Baker

— Flowers sparsely pubescent; midrib and lateral veins impressed on upper surface; domatia covered with reddish hairs ................................... O. ivohibensis van der Werff , sp. nov.

11. Domatia along lateral veins, often also at the junction of lateral veins and midrib; terminal buds glabrous ............................................................................. O. perforata Kosterm.

— Domatia restricted to junction of lateral veins and midrib or, if occasionally present along lateral veins, then terminal buds pubescent ............................................................... 12

12. Inflorescences and young twigs pilose, with erect hairs ............................................. 13

— Inflorescences and young twigs puberulous, with short appressed hairs or glabrous ........ 14

13. Outer surface of tepals pubescent, inner surface with a few hairs in the center ............... ................................................................................... O. tsaratananensis van der Werff

— Outer surface of tepals glabrous or nearly so; inner surface pubescent ........................... .................................................................................................. O. humbertii Kosterm.

14. Leaves tripliveined, to 6 cm long; young twigs and terminal buds sparsely pubescent .... .................................................................................................... O. foveolata Kosterm.

— Leaves pinnately veined, 5-20 cm long; young twigs and terminal buds densely pubescent or puberulous ........................................................................................................... 15

15. Flowers densely pubescent; leaves 10-20 × 4-8 cm ........................... O. humblotii Baill.

— Flowers very sparsely pubescent; leaves 5-10 × 3-4.5 cm ................................................ ........................................................................ O. zahamenensis van der Werff , sp. nov.

16. Lower leaf surface pubescent with erect hairs; midrib and lateral veins impressed on upper leaf surface ................................................................................. O. trichophlebia Baker

— Lower leaf surface glabrous or with some appressed hairs; venation raised or immersed on upper leaf surface ................................................................................................ 17

17. Filaments of inner 3 stamens fused in a tube .............. O. faucherei (Danguy) Kosterm.

— Filaments of inner 3 stamens free ............................................................................. 18

18. Plants entirely glabrous, including the outside of the flowers (terminal buds may have a fringe of hairs) .......................................................................................................... 19

— Plants with some pubescence, sometimes only on inflorescences and/or the outside of the flowers ...................................................................................................................... 22

19. Leaves 3-5.5 cm long, 1.5-2 cm wide .................. O. glaberrima van der Werff , sp. nov.

— Leaves 6-16 cm long, 2-7 cm wide ........................................................................... 20

20. Leaf apices obtuse; leaf margin inrolled; tall tree ....... O. madagascariensis (Meisn.) Palacký

— Leaf apices acuminate or acute; leaf margin flat; shrub or small tree ......................... 21

21. Reticulation raised on both surfaces; lower surface minutely and densely gland-dotted; pedicels c. 5 mm long ................................................... O. sambiranensis van der Werff

— Reticulation immersed, not visible; lower surface not gland-dotted; pedicels 10-15 mm long ............................................................................ O. longipedicellata van der Werff

22. Indument restricted to inflorescences and/or flowers; terminal buds glabrous ........... 23

— Indument not restricted to inflorescences and/or flowers; at least terminal buds pubescent ................................................................................................................................. 24

23. Leaf blades to 7 cm long; reticulation immersed on lower leaf surface ........................... ..................................................................................................... O. elliptica Kosterm.

— Leaf blades 7-12 cm long; reticulation raised on lower surface ....................................... ........................................................................................... O. cryptocaryoides Kosterm.

24. Leaf blades decurrent on the petiole; the base of the leaf revolute-auriculate ............. 25

— Leaf blades not decurrent on the petiole, or if decurrent, not revolute-auriculate ...... 26

25. Leaves 10-15 cm long, reticulation raised; leaf apices acute ........................................ .......................................................................................... O. auriculiformis Kosterm.

— Leaves to 7 cm long, reticulation immersed; leaf apices obtuse .......... O. involuta Kosterm.

26. Reticulation raised on upper leaf surface ................................................................... 27

— Reticulation immersed on upper leaf surface ............................................................ 31

27. Flowers sessile; bracts often present in the inflorescences at anthesis .............................. .................................................................................................. O. sessiliflora Kosterm.

— Flowers pedicellate, the pedicels at least as long as the flowers; bracts absent at anthesis ...... ................................................................................................................................. 28

28. Young twigs densely pubescent with short, erect hairs; leaf margin revolute and shortly decurrent on the petiole ............................................................ O. rigidifolia Kosterm.

— Young twigs appressed pubescent or with ascending hairs; leaf margin not revolute and not decurrent on the petiole ..................................................................................... 29

29. Inflorescences 2-4 cm long; reticulation fine .......................... O. cymosa (Nees) Palacký

— Inflorescences 3-7 cm long; reticulation lax .............................................................. 30

30. Mature leaves to 3 cm wide ....................................................... O. eriothyrsa Kosterm.

— Mature leaves 5-10 cm wide .......................................................... O. nervosa Kosterm.

31. Leaves opposite or subopposite .............................. O. racemosa (Danguy) Kosterm. s.l.

— Leaves alternate ........................................................................................................ 32

32. Receptacle densely pubescent inside ......................................................................... 33

— Receptacle glabrous inside; leaves usually less than 10 cm long ................................. 34

33. Leaves 8-15 cm long, elliptic to narrowly elliptic, the margin flat .............................. .............................................................................................. O. macrocarpa Kosterm.

— Leaves to 6 cm long, broadly elliptic to elliptic, the margin inrolled .............................. .................................................................................................. O. rigidifolia Kosterm.

34. Inflorescences in the axils of bracts at the base of recent year’s growth; leaf apices rounded ..................................................................................................... O. brevipes Kosterm.

— Inflorescences in the axils of leaves or along leaf less short shoots; leaf apices mostly acute ......................................................................................................................................... 35

35. Leaf apices caudate; leaves broadly elliptic, with immersed reticulation ......................... ............................................................................................... O. caudatifolia Kosterm.

— Leaf apices (bluntly) acute; leaves elliptic, reticulation raised on lower surface or immersed ................................................................................................................................. 36

36. Inflorescences along leafless short shoots, these with persisting bracts, 3-6 mm long, near their tips ................................................................................................................... 37

— Inflorescences along leafless short shoots without persisting bracts or inflorescences in the axils of normal leaves ............................................. O. racemosa (Danguy) Kosterm. s.l.

37. Flowers 6-8 mm in diameter; leaves 7-13 × 2.5-6 cm ................................................. ........................................................................... O. spanantha van der Werff , sp. nov.

— Flowers 5-6 mm in diameter; leaves 5-9 × 1.5-3.5 cm ................................................ ............................................................................ O. ambrensis van der Werff , sp. nov.

ALTERNATIVE KEY FROM COUPLET 26 ONWARDS

26. Inside of the receptacle pubescent ............................................................................. 27

— Inside of the receptacle glabrous ............................................................................... 30

27. Reticulation immersed on upper surface; leaves narrowly elliptic to elliptic ................... ............................................................................................... O. macrocarpa Kosterm.

— Reticulation raised on upper surface; leaves elliptic ................................................... 28

28. Young twigs densely tomentellous; leaf apices obtuse ................. O. rigidifolia Kosterm.

— Young twigs appressed pubescent, often sparsely so; leaf apices mostly acute ............ 29

29. Inflorescences 2-4 cm long; reticulation fine .......................... O. cymosa (Nees) Palacký

— Inflorescences 3-7 cm long; reticulation lax ................................... O. nervosa Kosterm.

30. Reticulation coarse and raised on the lower leaf surface ............................................ 31

— Reticulation immersed on lower leaf surface or if somewhat raised, reticulation fine ...... 32

31. Inflorescences and pedicels moderately to densely pubescent; leaves to 3,5 cm wide ...... .................................................................................................. O. eriothyrsa Kosterm.

— Inflorescences and pedicels subglabrous; leaves 6-10 cm wide .... O. cryptocaryoides Kosterm.

32. Flowers sessile ............................................................................ O. sessiliflora Kosterm.

— Pedicels about as long as the flowers ......................................................................... 33

33. Inflorescences in the axils of bracts at the base of recent year’s growth; leaf apices rounded ..................................................................................................... O. brevipes Kosterm.

— Inflorescences in the axils of leaves or along leaf less short shoots; leaf apices mostly acute ................................................................................................................................. 34

34. Leaf apices caudate; leaves broadly elliptic, with immersed reticulation ......................... ............................................................................................... O. caudatifolia Kosterm. — Leaf apices (bluntly) acute; leaves elliptic, reticulation raised on lower surface or immersed ................................................................................................................................. 35

35. Inflorescences along leafless short shoots, these with persisting bracts, 3-6 mm long, near their tips ................................................................................................................... 36

— Inflorescences along leafless short shoots without persisting bracts or inflorescences in the axils of normal leaves............................................... O. racemosa (Danguy) Kosterm. s.l.

36. Flowers 6-8 mm in diameter; leaves 7-13 × 2.5-6 cm ................................................. ........................................................................... O. spanantha van der Werff , sp. nov.

— Flowers 5-6 mm in diameter; leaves 5-9 × 1.5-3.5 cm ................................................. ............................................................................ O. ambrensis van der Werff , sp. nov.