Geonoma concinna Burret (1930a: 229)

Henderson, Andrew, 2011, A revision of Geonoma (Arecaceae), Phytotaxa 17, pp. 1-271 : 49-50

11. Geonoma concinna Burret (1930a: 229) . Type: COLOMBIA. Antioquia: Tabor, 1950 m, 27 January 1880, W. Kalbreyer 1367 (holotype B, destroyed). Neotype (selected by Bernal et al. 1989): COLOMBIA. Antioquia: carretera Granada-San Luis, 5.5 km adelante de El Chocó, 1750 m, 20–21 September 1987, R. Bernal & L. Tobón 1358 (neotype COL!, isoneotype NY!).

Plants 1.8(1.5–2.5) m tall; stems 3.5 m tall, 1.0(0.9–1.2) cm in diameter, clustered, cane-like; internodes 3.5(2.5–4.5) cm long, yellowish and smooth. Leaves 8 per stem, undivided or irregularly pinnate, not plicate, bases of blades running diagonally into the rachis; sheaths 14.0 cm long; petioles 9.0 cm long, drying green or yellowish; rachis 27.4(20.3–38.5) cm long, 3.4(3.1–3.8) mm in diameter; veins raised and rectangular in cross-section adaxially; pinnae 2(1–4) per side of rachis; basal pinna 30.5(24.0–37.0) cm long, 8.2(8.0–8.4) cm wide, forming an angle of 44(35–55)° with the rachis; apical pinna 17.9(14.0–20.8) cm long, 10.0(8.0– 12.0) cm wide, forming an angle of 38(32–42)° with the rachis. Inflorescences branched 2 orders; prophylls and peduncular bracts not ribbed with elongate, unbranched fibers, flattened, deciduous; prophylls 10.8(9.0– 12.5) cm long, not short and asymmetrically apiculate, the surfaces ridged with close, equal, parallel, nondividing ridges, scarcely tomentose between the ridges, without unequally wide ridges; peduncular bracts 7.2 cm long, well-developed, inserted 0.4(0.2–0.6) cm above the prophyll; peduncles 11.1(8.2–13.2) cm long, 3.6(3.0–4.2) mm in diameter; rachillae 19(13–21), 1.7(8.0–14.8) cm long, 1.7(1.2–2.7) mm in diameter, the surfaces without spiky, fibrous projections or ridges, drying brown, with faint to pronounced, short, transverse ridges, not filiform and not narrowed between the flower pits; flower pits spirally arranged, glabrous internally; proximal lips without a central notch before anthesis, not recurved after anthesis, hood-shaped at anthesis, sometimes splitting post-anthesis; proximal and distal lips drying the same color as the rachillae, not joined to form a raised cupule, the proximal lip margins overlapping the distal lip margins; distal lips welldeveloped; staminate and pistillate petals not emergent, not valvate throughout; staminate flowers deciduous after anthesis; stamens 6; thecae diverging at anthesis, inserted almost directly onto the filament apices, the connectives bifid but scarcely developed; anthers short and curled over at anthesis; non-fertilized pistillate flowers deciduous after anthesis; staminodial tubes crenulate or shallowly lobed at the apex, those of nonfertilized flowers not projecting and persistent after anthesis; fruits 7.7(7.1–8.3) mm long, 6.7(6.1–7.3) mm in diameter, the bases without a prominent stipe, the apices not conical, the surfaces not splitting at maturity, without fibers emerging, bumpy from the numerous, subepidermal, tangential, short fibers present, these coming to a point at fruit apices; locular epidermis with operculum, smooth, without pores.

Taxonomic notes:— Geonoma concinna is a member of the G. congesta clade, and most closely related to G. concinnoidea , from which it differs by its fruits without fibers emerging. Geonoma concinna was considered by Henderson et al. (1995) to be a poorly understood species. This is still true because of the lack of specimens (only four specimens known). In Henderson et al., specimens from Panama were included in G. concinna ; here they are recognized as a distinct species, G. concinnoidea .

Subspecific variation:— One trait (leaf division) varies within this species. There is geographic discontinuity and specimens occur in two separate areas in Colombia. There are too few specimens for analysis. Based on the trait distribution and geography, two subgroups can be recognized and these are treated as subspecies (subspp. concinna , simplex). Subspecies concinna occurs at higher elevations than subsp. simplex ; 1475(1200–1750) versus 777(755–800) m elevation.

Key to the subspecies of G. concinna

1 Leaves pinnate; Central Cordillera ....................................................................................................... subsp. concinna - Leaves undivided; Western Cordillera ..................................................................................................... subsp. simplex