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Article4. Key to the Families of Trees and Shrubs Springfield Centre for Environmental Protection, Research and Education (formerly Springfield and Mt. Joy Estates) Dominica, W.I.  

By Allan P. Drew
State University of New York
College of Environmental Science and Forestry
Syracuse, New York

 

            The following key is based on vegetative rather than floral characteristics and is designed to identify with a 10X hand lens the correct families of individual dicotyledonous trees and shrubs found on the Springfield property of the Archbold Tropical Research and Education Consortium in Dominica.  Springfield Centre is located at 380m elevation in the Antrim Valley north of Roseau in the lower rain forest zone.  Secondary forest characterizes most of the property which between 1936 and 1979 was cultivated and comprised of Springfield and Mt. Joy estates. 
Species belonging to thirty-three families of Dicotyledoneae including three sub-families have been identified.  Names of genera appear in parentheses when the genera noted are the only ones having the given character(s) and are the only genera of the family found at Springfield.  New families, if found, will be added as necessary in the future and the key updated.

  Vegetative Characteristic Family  
1. Compound leaves   2
1. Simple leaves   10
       
2. Opposite leaves BIGNONIACEAE  
2. Alternate leaves   3
       
3. Leaves with stipules   4
3. Leaves without stipules   7
       
4. Leaves palmate BOMBACACEAE  
4. Leaves pinnate of bipinnate   5
       
5. Leaves imparipinnate PAPILIONACEAE (FABACEAE)  
5. Leaves paripinnate or bipinnate   6
       
6. Leaves bipinnate with nectaries MIMOSACEAE (FABACEAE)  
6. Leaves paripinnate or bipinnate without nectaries CAESALPINIACEAE (FABACEAE)  
       
7. Leaves with pellucid dots RUTACEAE  
7. Leaves without pellucid dots   8
       
8. Leaves with mango or turpentine odor and without bitter taste BURSERACEAE  
8. Leaves without mango or turpentine odor   9
       
9. Leaves with bitter taste, clear sap SIMAROUBACEAE  
9. Leaves with milky sap CARICACEAE  
       
10. Leaves opposite or whorled   11
10. Leaves alternate   17
       
11. Leaves with stipules   12
11. Leaves without stipules   13
       
12. Stipules interpetiolar RUBIACEAE  
12. Stipules  intrapetiolar or free MALPIGHIACEAE  
       
13. Leaves with scalariform veins MELASTOMATACEAE  
13. Leaves without scalariform veins   14
       
14. Leaf veins prominent   15
14. Leaf veins obscure, finger-like with creamy latex CLUSIACEAE  
       
15. Leaves with pinnate veins and with fused marginal vein, lacking latex MYRTACEAE  
15. Leaves with pinnate, but open veins   16
       
16. Branchlets quadrangular VERBENACEAE  
16. Branchlets with white latex APOCYNACEAE  
       
17. Leaves with stipules   18
17. Leaves without stipules   27
       
18. Bark stringy when peeled from twig   19
18. Bark not stringy when peeled from twig   21
       
19. Stems mucilaginous, leaves 3-5 veined   20
19. Stems not mucilaginous, leaves 3-5 veined ELAEOCARPACEAE  
       
20. Petals yellow (Guazuma) or united sepals a cream color (Sterculia) STERCULIACEAE  
20. Petals orange-red to dark crimson (Hibiscus) MALVACEAE  
       
21. Stems with white latex   22
21. Stems without white latex   23
       
22. Prominent terminal stipule scar, false marginal leaf vein, transverse lenticels on the stem MORACEAE  
22. Extrafloral nectaries present, leaves spirally arranged EUPHORBIACEAE  
       
23. Stems with brownish exudation, prominent terminal stipule scar, leaves palmately lobed, white beneath CECROPIACEAE  
23. Stems without exudation   24
       
24. Stipules intrapetiolar   25
24. Stipules not intrapetiolar   26
       
25. Stipules hairy, bark brittle CHRYSOBALANACEAE  
25. Stipules not hairy, bark not brittle, central leaf area different texture ERYTHROXYLACEAE  
       
26. Leaf nodes swollen, inflorescence a vertical spike PIPERACEAE  
26. Trunk fluted, blaze turns orange DICHAPETALACEAE  
       
27. Bark stringy when peeled from the twig   28
27. Bark not stringy when peeled from the twig   30
       
28. Leaves aromatic, distichous ANNONACEAE  
28. Leaves not aromatic or distichous   29
       
29. Sympodial branching, verticillate at ends (Cordia) BORAGINACEAE  
29. Non sympodially branched shrub or tree to 15m, bitter inner bark THYMALAEACEAE  
       
30. Leaves aromatic (or with bad odor)   31
30. Leaves non aromatic   34
       
31. Leaves with mango odor, resinous exudate is dark upon drying ANACARDIACEAE  
31. Leaves with other than mango odor   32
       
32. Leaves with bad odor, often having stellate hairs SOLANACEAE  
32. Leaves with pleasant smell   33
       
33. Leaves with pellucid dots, citrus smell RUTACEAE  
33. Leaves without pellucid dots, spirally arranged, sulcate stem LAURACEAE  
       
34. Leaves with white latex   35
34. Leaves with other than white latex or none   36
       
35. Turbinate flower buds, fruit in pairs, finger-like glands APOCYNACEAE  
35. Flower buds not turbinate, bottle-shaped petiole SAPOTACEAE  
       
36. Leaves with reddish exudation, falsely whorled long branches, distichous MYRISTICACEAE  
36. Leaves without latex, obovate, crowded near branch ends, sympodial branching COMBRETACEAE  

Acknowledgements:
            I am grateful to Dr. Humberto Jiménez-Saa of the Tropical Science Center, San Jose, Costa Rica for helpful instruction in tropical dendrology and to Dr. Steven Hill of the Illinois Natural History Survey whose Springfield herbarium collection of the flora of Dominica was invaluable in the preparation of this key.

May 4, 2006

 

 

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