Geonoma oldemanii de Granville (1975: 553)

Henderson, Andrew, 2011, A revision of Geonoma (Arecaceae), Phytotaxa 17, pp. 1-271 : 107

42. Geonoma oldemanii de Granville (1975: 553) . Type: FRENCH GUIANA. St. Georges d’Oyapock, Crique Cabaret, 1 October 1973, J.-J. de Granville 1992 (holotype CAY n.v., isotypes P!, US!).

Plants 3.5(2.0–7.0) m tall; stems 1.6(0.2–2.5) m tall, 2.0(1.7–2.4) cm in diameter, clustered, cane-like; internodes 1.7(0.8–2.2) cm long, yellowish and smooth. Leaves 14(12–19) per stem, undivided, not plicate, bases of blades recurved against the rachis; sheaths 14.0(10.0–17.5) cm long; petioles 9.1(1.0–18.0) cm long, drying green or yellowish; rachis 125.9(107.5–149.0) cm long, 6.5(4.3–9.7) mm in diameter; veins not raised or slightly raised and triangular in cross-section adaxially; pinnae 1 per side of rachis; basal pinna length and width not applicable, forming an angle of 9(4–15)° with the rachis; apical pinna 26.8(19.0–38.0) cm long, width not applicable, forming an angle of 16(12–18)° with the rachis. Inflorescences unbranched; prophylls and peduncular bracts ribbed with elongate, unbranched fibers, both bracts tubular, narrow, elongate, closely sheathing the peduncle, more or less persistent; prophylls 29.5(25.0–37.5) cm long, not short and asymmetrically apiculate, the surfaces not ridged, without unequally wide ridges; peduncular bracts 23.3(21.5–25.0) cm long, well-developed, inserted 3.7(3.3–4.0) cm above the prophyll; peduncles 41.5(39.5– 42.5) cm long, 4.3(3.4–5.5) mm in diameter; rachillae 1, 32.7(26.0–45.0) cm long, 7.8(6.5–10.3) mm in diameter, the surfaces without spiky, fibrous projections or ridges, drying brown or yellow-brown, without short, transverse ridges, not filiform and not narrowed between the flower pits; flower pits spirally arranged, glabrous internally; proximal lips with a central notch before anthesis, often the two sides of the notch overlapping, not recurved after anthesis, not hood-shaped; 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 well-developed; staminate and pistillate petals not emergent, not valvate throughout; staminate flowers deciduous after anthesis; stamens 6; thecae diverging at anthesis, inserted directly onto the apiculate filament apices; anthers not short and curled at anthesis, usually elongate, spiraled and twisted or sometimes remaining straight; non-fertilized pistillate flowers deciduous after anthesis; staminodial tubes lobed at the apex, the lobes spreading at anthesis, acuminate, those of non-fertilized pistillate flowers not projecting and persistent after anthesis; fruits 16.2(14.4–17.7) mm long, 13.7(12.4–16.3) mm in diameter, the bases without a prominent stipe, the apices not conical, the surfaces not splitting at maturity, without fibers emerging, not bumpy, not apiculate; locular epidermis with operculum, smooth, with pores.

Distribution and habitat:— From 0°15’S– 5°03’N and 50°30’– 56°30’W in the eastern Amazon region in French Guiana and Brazil at 51(20–100) m elevation in coastal, terra firme forest or lowland rainforest ( Fig. 29 ).

Taxonomic notes:— Geonoma oldemanii is related to G. triglochin and G. umbraculiformis . It differs from these in its prophylls and peduncular bracts which are ribbed with elongate, unbranched fibers, and both bracts are tubular, narrow, elongate, closely sheath the peduncle, and are more or less persistent

Subspecific variation:— No trait varies within this species. There is geographic discontinuity, and specimens come from three areas—French Guiana, Marajó, and the Rio Trombetas, the last two in Brazil. There are too few specimens to test for differences, and the gaps are likely to be artifacts of insufficient collecting.

One specimen from French Guiana (Roncal 396 —not included in the above description) is much smaller than other specimens, and resembles G. stricta subsp. pliniana , with which it occurs.

Figures

FIGURE 29. Distribution maps of Geonoma oldemanii, G. oligoclona, G. operculata, and G. orbignyana subsp. orbignyana.