KEYS TO GENERA IN CENTRAL AMERICA [pdf]
(Guatemala and Belize to Panama)
by William R. Anderson and Christiane Anderson
Key to specimens bearing flowers [fruits]
1. Flowers all cleistogamous (ca. 1.5 mm in diameter, without visible petals, androecium, or gynoecium). [photo
1. Flowers (some or all) chasmogamous (at least 6 mm in diameter, with showy petals, the androecium and gynoecium visible).
2. Petals pink and/or white or white turning red or yellowish in age, pink turning reddish in age, lilac, or lilac fading to white.
2. Petals yellow or greenish yellow, or yellow with a red central blotch, or yellow turning red or orange, or yellow and red.
3. Bracteoles (some) terminating in a stalked peltate gland; trees or shrubs.
3. Bracteoles all eglandular or bearing 1 or 2 tiny abaxial or basal glands; trees, shrubs, or woody vines.
4. Anthers with 2 dark longitudinal wings on outer locules; ovary tricarpellate; styles 3, slender and subulate, tapering to minute stigmas; lamina eglandular in upper (adaxial) surface.
4. Anthers unwinged; ovary bicarpellate; 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.
5. Trees or shrubs; inflorescence unbranched.
5. Woody vines, or if described as shrubby the inflorescence branched.
6. Inflorescence terminating a leafy shoot, an elongated pseudoraceme or with some bracts subtending few-flowered cincinni.
6. Inflorescence lateral, axillary to current leaves or bracts or above the scars of fallen leaves or bracts, consisting of fascicles, umbels, corymbs, or short condensed pseudoracemes.
7. Pedicels sessile; stipules intra- and epipetiolar, the members of a pair proximally connate and distally distinct; leaves eglandular; anthers with the outer locules bearing introrse longitudinal wings, the connective exceeding locules at apex; styles slender and subulate with minute stigmas; fruit dry, dehiscent.
7. Pedicels pedunculate; stipules interpetiolar, distinct or each connate with a stipule from opposite petiole to form an interpetiolar pair; leaves with lamina usually bearing 2 (–10) glands impressed in abaxial surface; anthers unwinged, the connective not exceeding locules at apex; styles of uniform thickness, the apex with a large internal or subterminal stigma and dorsally rounded, truncate, or hooked; fruit fleshy, mostly indehiscent (a few species with the pyrenes separating at maturity).
8. Corolla radially symmetrical or nearly so, the petals subequal in size and shape but one with the claw wider than the other 4, pure white; pedicels sessile; sepals all eglandular.
8. Corolla bilaterally symmetrical, the posterior petal obviously different from the other 4, the petals white in a few species but mostly at least partly pink or lilac; pedicels mostly pedunculate, sessile in a few species; sepals all eglandular or (much more often) the lateral 4 sepals biglandular and the anterior sepal eglandular.
9. Styles with stigmas terminal and without any sort of dorsal extension at apex; anthers strongly heteromorphic. [sample styles
9. Styles with stigmas internal, the apex dorsally rounded, truncate, acute, or extended into a short hook; anthers ± alike. [sample styles
10. Flowers borne in umbels or corymbs of (2) 3–7 (–10); glands usually present on abaxial surface of lamina, swollen to peltate, or if flush with leaf surface the petals abaxially winged.
10. Flowers borne in elongated to condensed pseudoracemes; glands usually present on lamina, on margin or abaxial surface; petals abaxially smooth.
11. Glands on lamina (if present) strictly marginal; calyx glands sericeous, especially toward margins; stipules absent or borne on base of petiole.
11. Glands on lamina (if present) flush with leaf surface; calyx glands glabrous; stipules borne on stem between petioles.
12. Bracteoles larger than bracts, globose-cymbiform, borne just below flower, enclosing bud until flower opens; peduncles well developed, the pedicels absent or up to 2 (–5) mm long in fruit.
12. Bracteoles mostly similar to bracts or smaller than them, if larger not enclosing bud until flower opens; peduncles absent or short relative to the well-developed pedicels.
13. Petals abaxially ± densely sericeous or appressed-tomentose.
13. Petals abaxially glabrous or sparsely sericeous on midrib.
14. Bracts, bracteoles, and sepals bearing many stalked glands all around the margin.
14. Bracts, bracteoles, and sepals with their margins eglandular.
15. Styles apparently 2, the anterior style rudimentary or absent.
15. Styles 3, all well developed and ± equal.
16. Lateral 4 sepals each bearing 1 large central abaxial gland and the anterior sepal eglandular, or all 5 sepals eglandular.
16. Lateral 4 sepals each bearing 2 large abaxial glands, the anterior sepal eglandular.
17. Apex of styles with stigmas quite terminal and without any sort of dorsal extension; anthers pubescent on locules; pedicels sessile.
17. Apex of styles with stigmas internal and dorsally rounded or truncate; anthers glabrous; pedicels pedunculate.
18. Stipules borne on petiole at or just above base; stigmas transversely expanded.
18. Stipules borne on stem between petioles; stigmas round.
19. Stamens 5.
19. Stamens 10.
20. Styles slender and subulate, tapering to minute stigmas; trees, shrubs, or subshrubs. [sample styles
20. Styles slender to stout, of uniform thickness or widened at apex, the stigmas large; trees, shrubs, or vines. [sample styles
21. Leaves eglandular; pedicels sessile in most species; fruit fleshy, the seeds borne in an indehiscent trilocular stone.
21. Leaves mostly bearing glands on petiole and/or proximally on margin of lamina; pedicels pedunculate; fruit dry, breaking apart into 3 1-seeded cocci.
22. Petals concealed by sepals during enlargement of bud, until anthesis.
22. Petals (at least the outermost) exposed during enlargement of bud.
23. Leaves densely and persistently metallic-sericeous below.
23. Leaves glabrate below or only very thinly sericeous, the hairs not hiding epidermis.
24. Petals strongly dissimilar in color and margin, the lateral 4 pure yellow and ± entire, the posterior reddish or yellow with red veins and deeply lacerate-fimbriate.
24. Petals ± alike in color and margin, although posterior petal may differ from lateral 4 in size, shape, and stance.
25. Apex of styles (2 or all 3) dorsally extended into a long hook or flap-bearing appendage.
25. Apex of styles dorsally rounded, truncate, acute, or short-hooked.
- sample taxa - photos: S. bannisterioides, S. ciliatum, S. ellipticum, S. puberum
- drawings: S. adenophorum, S. bannisterioides, S. hypargyreum, S. lindenianum, S. panamense, S. puberum, S. retusum, S. tonduzii
26. Trees or shrubs; stipules borne on base of petiole; 1 or both bracteoles often bearing 1 (2) abaxial glands; carpels 2 or 3, developing into an indehiscent fleshy fruit; styles 2 or 3, distinct or partly to completely connate.
26. Woody vines, occasionally shrubby but then without the characters of stipules, bracteoles, carpels, fruits, and styles given above for Bunchosia.
27. Petiole biglandular at base.
27. Petiole eglandular at base.
28. Pedicels sessile or raised on a peduncle up to 1.5 mm long.
28. Pedicels pedunculate, the peduncle mostly over 1.5 mm long.
29. Apex of styles with stigmas internal and dorsally rounded, truncate, or acute; stipules 1–8 mm long, subulate, borne on petiole between base and apex, persistent.
29. Apex of styles with stigmas terminal and without any sort of dorsal extension; stipules borne on stem between petioles, triangular, less than 1 mm long, persistent or deciduous.
30. Petals lacerate, laciniate, or fimbriate; flowers borne mostly in umbels of 4, rarely in umbels or very short pseudoracemes of 3–4 pairs.
30. Petals entire or denticulate; flowers borne in short dense pseudoracemes of 8–25.
31. Flowers borne in umbels of 4 (–6).
31. Flowers borne in elongated to congested pseudoracemes, or in corymbs of more than 6 flowers.
32. Lamina densely and persistently metallic-sericeous below with the epidermis ± completely hidden by the vesture, the hairs originally bronze or golden but fading to silver in age; glands on lamina borne on abaxial surface between midrib and margin.
32. Lamina mostly ± glabrescent below at maturity, if persistently subsericeous the lamina glands restricted to margin.
33. Petioles of larger leaves (1.5–) 2 cm long or longer, usually bearing a pair of large glands at or slightly below apex or slightly above apex against midrib.
33. Petioles of larger leaves up to 0.9 cm long, eglandular.
34. Flowers borne in corymbs.
34. Flowers borne in elongated pseudoracemes.