Rudgea, Salisbury (1807: 327), Salisbury, 1807

Key to the species View in CoL

1. Leaves ternate; stipular appendages all dorsal and shorter than sheath ( Fig. 1B View FIGURE 1 ) ( Guyana, Venezuela, N. Brazil, Peru) ................... .................................................................................................................................................................................. R. coussareoides View in CoL

- Leaves opposite; stipular appendages exceeding sheath, except in R. bolivarensis View in CoL ...........................................................................2

2. Stipules narrowly tubular with sheath longer than broad (but often splitting very early at flower-bearing nodes); inflorescences glabrous, sometimes with large foliaceous bracts; corolla lobes corniculate, glabrous outside ........................................................3

- Stipules with sheath broader than long; inflorescences puberulous (rarely glabrous in R. maypurensis View in CoL ), never with large foliaceous bracts; corolla lobes not corniculate, or, if corniculate, pubescent or puberulous outside at least near the apex ..............................4

3. Stipules with dorsal appendages inserted near the base; inflorescence subcapitate with large foliaceous imbricate bracts 10–20 x 2–7 mm; corolla tube 13 mm long ( French Guiana) ......................................................................................................... R. pungens View in CoL

- Stipules with dorsal appendages inserted in upper half; inflorescence distinctly branched with small subulate bracts 3–5 mm long; corolla tube 6 mm long ( French Guiana: Kaw Mountain) ................................................................................................ R. billietiae

4. Stipules ± truncate with appendages shorter than sheath ( Fig. 1A View FIGURE 1 ); leaves thickly coriaceous, with conspicuously reticulate tertiary venation; corolla lobes glabrous outside and not corniculate ( Venezuela, Guyana, N Brazil) ................................... R. bolivarensis View in CoL

- Stipules with appendages exceeding sheath; leaves with tertiary venation usually rather obscure; corolla lobes corniculate except in R. maypurensis View in CoL ...............................................................................................................................................................................5

5. Stipules with dorsal appendages recurved, free at base or shortly connate into a keel ( Fig. 1E View FIGURE 1 ); leaves slightly cordate to rounded at base; corolla lobes not corniculate; pyrenes dorsally verrucose ( Venezuela, N Brazil,?SE Colombia)................ R. maypurensis View in CoL

- Stipules with appendages all erect, the dorsal ones connate into a keel ( Fig. 1C–D & F View FIGURE 1 ); leaves cuneate to obtuse at base, never cordate; corolla lobes corniculate; pyrenes not verrucose dorsally....................................................................................................6

6. Calyx lobes 3–5 mm long, linear ( Fig. 2F View FIGURE 2 ); bracts 5–7 mm long, linear to narrowly lanceolate; corolla lobes usually with linear appendages (rarely these short and blunt); fruits ellipsoid to globose; leaf blade with secondary veins weakly ascending ( Guyana)...................................................................................................................................................................... R. tanaosepala View in CoL

- Calyx lobes 0.7–2 mm long, semicircular to subulate ( Fig. 2 View FIGURE 2 C-D); bracts usually <3 mm long, or if longer (to 10 mm in R. hostmanniana View in CoL ) then relatively broad; corolla lobes with short and blunt appendages; fruits obovoid, rarely subglobose; leaf blade with secondary veins usually strongly ascending...............................................................................................................................7

7. Stipules with central keel much exceeding the lateral appendages ( Fig. 1D View FIGURE 1 ); leaves acute (rarely obtuse) at base, with petiole 0.5–2 cm long; inflorescence pyramidal or rarely hemispherical; calyx lobes triangular to semicircular ( Fig. 2D View FIGURE 2 ); corolla tube 3–5 mm long (widespread) .................................................................................................................................................... R. hostmanniana View in CoL

- Stipules with central keel roughly equalling the lateral appendages ( Fig. 1C View FIGURE 1 ); leaves obtuse at base, with petiole 0.2–0.8 cm long; inflorescence hemispherical; calyx lobes subulate to narrowly triangular ( Fig. 2C View FIGURE 2 ); corolla tube 5–7 mm long ( Guyana, Suriname) ........................................................................................................................................................................ R. cornigera View in CoL