KEYS TO GENERA IN CENTRAL AMERICA [pdf]
(Guatemala and Belize to Panama)
by William R. Anderson and Christiane Anderson
Key to specimens bearing fruits [flowers]
1. Fruit with a soft, fleshy, edible exocarp, indehiscent or in a few species the flesh-covered pyrenes separating at maturity; trees, shrubs, or subshrubs.
1. Fruit dry; trees, shrubs, or slender to woody vines.
2. Leaves and bracteoles eglandular; styles slender and subulate, the stigmas minute; inflorescence terminating a leafy shoot, an elongated pseudoraceme or with some bracts subtending few-flowered cincinni. [sample styles
2. Leaves usually bearing glands impressed in abaxial surface of lamina; bracteoles eglandular or some bracteoles bearing large abaxial glands; styles slender to stout, of uniform thickness or widened at apex, the stigmas large; inflorescence axillary, without leaves or with at most 1 pair of leaves, elongated or condensed and corymbiform or umbellate. [sample styles
3. Flowers borne in elongated pseudoracemes; bracteoles (one or both) often bearing 1 large abaxial gland, sometimes 2; styles 2 or 3, distinct or partly to completely connate and then apparently only 1; stipules borne on base of petiole.
3. Flowers borne in umbels or corymbs or short condensed pseudoracemes; bracteoles all eglandular; styles 3, distinct; stipules borne on stem between petioles.
4. Fruit indehiscent at maturity, a hard nut subtended by 5 dry wings formed by enlargement of the sepals; woody vines; Costa Rica.
4. Fruit schizocarpic at maturity, breaking apart into mericarps; trees, shrubs, or slender to woody vines.
5. Mericarps or cocci smooth or at most ribbed, unwinged; trees or shrubs.
5. Mericarps winged, the wing(s) reduced in some species to winglets; trees, shrubs, or slender to woody vines.
6. Fruit consisting of 2 mericarps, developing from a bicarpellate ovary; styles 2, stout, untapered, the stigmas broad; lamina bearing a row of small glands in upper (adaxial) surface, the glands distal and set in from margin.
6. Fruit consisting of 3 mericarps, developing from a tricarpellate ovary; styles 3, slender and subulate, tapering to minute stigmas; lamina eglandular in upper (adaxial) surface.
7. Bracteoles (some) terminating in a stalked peltate gland.
7. Bracteoles all eglandular.
8. Flowers borne in sessile or subsessile fascicles of 4–6 in the axils of leaves or bracts or above the scars of fallen leaves or bracts; leaves eglandular; pedicels sessile.
8. Flowers borne in terminal elongated pseudoracemes or panicles of several pseudoracemes; leaves mostly bearing glands on petiole and/or proximally on margin of lamina; pedicels pedunculate.
9. Mericarps with outgrowths or wings very short relative to size of nut.
9. Mericarps samaroid, with either dorsal or lateral wing(s) (or both) well developed.
10. Flowers borne in elongated many-flowered pseudoracemes; sepals revolute at apex.
10. Flowers borne in umbels of (3) 4 (–6); sepals erect or appressed.
11. Pedicels subsessile or borne on peduncles up to 0.2 times as long as pedicels; Atlantic coast.
11. Pedicels and peduncles subequal in length; Pacific coast of Panama.
12. Samaras with dorsal wing dominant, the nut bearing on its sides only short winglets or crests or quite smooth.
12. Samaras with lateral wing(s) dominant, the dorsal wing smaller or reduced to a winglet or crest, or absent.
13. Wing of samara with the abaxial edge thickened, the veins diverging and branching from it toward the thinner adaxial edge.
13. Wing of samara with the adaxial edge thickened, the veins diverging and branching from it toward the thinner abaxial edge.
14. Lamina densely and persistently metallic-sericeous below.
14. Lamina glabrate below at maturity, or thinly sericeous or tomentose, or tomentose with T-shaped hairs.
15. Petiole eglandular or bearing 1 or 2 pairs of small raised peltate glands on distal half; lamina often bearing 2–4 (5) pairs of small peltate and often stipitate glands on abaxial surface.
15. Petiole bearing 1 pair of large prominent glands at or just above or below the apex; other glands on lamina none or on margin.
16. Pedicels sessile or rarely raised on peduncles up to 1.5 mm long; flowers borne 6–8 per umbel or very short dense pseudoraceme.
16. Pedicels raised on peduncles (1.5–) 2 mm long or (often) longer; flowers borne 8–35 per umbel or congested pseudoraceme.
17. Lamina deeply auriculate at base with the lobes overlapping in larger leaves and fringed on the margin with filiform glands up to 5.5 mm long.
17. Lamina cuneate to cordate at base without overlapping lobes, the margin eglandular or with sessile glands.
18. Flowers borne in umbels or congested pseudoracemes of 7–50.
19. Flowers mostly borne in umbels, if in congested pseudoracemes the pedicels raised on peduncles at least 3 mm long.
19. Flowers borne in elongated pseudoracemes; pedicels sessile or raised on peduncles up to 1.5 mm long.
18. Flowers borne in umbels of (3) 4 (–6).
20. Pedicels raised on peduncles 2.5–34 mm long, expanded distally.
20. Pedicels sessile, not expanded distally.
21. Nut of samara smooth or at most rugose on sides.
21. Nut of samara bearing crests or winglets on sides.
- sample taxon - D. platyptera
22. Samara with the lateral wings rarely entire, usually each irregularly divided into 3–5 narrowly rectangular segments.
22. Samara with the lateral wings not irregularly divided.
23. Samara asymmetrical or, if symmetrical, V- or Y-shaped, at maturity dangling from a slender threadlike carpophore attached to underside of wing.
23. Samara symmetrical (X-shaped, elliptical, orbicular, triangular, or butterfly-shaped), not dangling from a carpophore at maturity.
24. Samara with 4 lateral wings, 2 on each side.
- sample taxa - photos: T. discolor, T. goudotiana, T. mucronata, T. styloptera, T. tinifolia
- drawings: T. discolor, T. heterophylla, T. mucronata, T. schiedeana, T. seleriana, T. styloptera, T. tinifolia
24. Samara with 1 continuous lateral wing or 2, 1 on each side.
25. Samara with the lateral wings confluent at least at base, confluent or notched to distinct at apex; lamina glands, if present, borne on abaxial surface between midrib and margin.
25. Samara with the 2 lateral wings distinct at both base and apex; lamina glands, if present, strictly marginal except often a pair at base against midrib.
26. Flowers borne in elongated or congested pseudoracemes or corymbs of 10 or more flowers, sometimes fewer on lateral branches of the inflorescence; samara up to 36 mm across.
26. Flowers borne in umbels of 4 or corymbs of 6; samara at least 45 mm across in its longest dimension.
27. Bracteoles globose-cymbiform, borne just below flower with the pedicel absent or very short [up to 2 (–5) mm long in fruit], the inner bracteole enclosing bud until anthesis, the outer enclosing bud and inner bracteole, the bracteoles persistent or deciduous before maturation of the fruit; samara orbicular, about as wide as high; anterior sepal eglandular, the lateral 4 each bearing 2 large, compressed, distinct or partially to completely connate abaxial glands; stipules borne on stem between petioles, caducous; Panama.
27. Bracteoles flat or concave but not enclosing bud, borne below a well-developed pedicel, persistent or deciduous in fruit; samara elliptical, much wider than high; sepals all eglandular or the lateral 4 each bearing 1 large abaxial gland; stipules borne on base of petiole, persistent; Panama and Costa Rica.
28. Pedicels sessile.
29. Flowers borne in umbels of 4–many; stipules 1–8 mm long, subulate, borne on petiole between base and apex; sepals all eglandular or the lateral 4 bearing (6–) 8 abaxial glands.
- sample taxa - photos: H. barclayana, H. fagifolia, H. faginea, H. grandifolia, H. reclinata, H. smilacina
- drawings: H. barclayana, H. fagifolia,H. faginea, H. grandifolia, H. reclinata, H. smilacina, H. ternifolia
29. Flowers borne in elongated pseudoracemes; stipules 0.1–0.9 mm long, triangular, borne on petiole at or slightly above base or on stem beside petiole, occasionally absent; sepals all eglandular.
28. Pedicels usually raised on a peduncle, rarely subsessile.
30. Bracts, bracteoles, and sepals bearing many stalked glands all around the margin.
30. Bracts, bracteoles, and sepals with their margins eglandular.
31. Lamina densely and persistently metallic-sericeous below; Panama and Costa Rica.
31. Lamina glabrous below or at most sparsely sericeous.
32. One bracteole of each pair bearing 1 large abaxial gland; pedicel shorter than peduncle or about the same length; petiole eglandular or (often) bearing 2 large protuberant glands on distal half.
32. Both bracteoles eglandular; pedicel much longer than peduncle; petiole eglandular or bearing 2–4 (–6) small glands at various heights.
33. Stipules borne on petiole at or just above base.
33. Stipules borne on stem between petioles.