Geonoma talamancana Grayum (1998: 324)

Henderson, Andrew, 2011, A revision of Geonoma (Arecaceae), Phytotaxa 17, pp. 1-271 : 147-148

61. Geonoma talamancana Grayum (1998: 324) . Type: COSTA RICA. Limón: Cantón de Limón, Cordillera de Talamanca, N flank of Fila de Matama in headwaters of Río Boyei, 9°45’N, 83°19’W, 1200–1300 m, 17 August 1995, M. Grayum 11033 (holotype MO!, isotypes CR!, INB!, K, NY!).

Plants 1.1(0.5–2.0) m tall; stems 1.1(1.0–1.3) m tall, 1.3 cm in diameter, solitary or clustered; internodes length no data, yellowish and smooth, or, if short and congested, not scaly. Leaves 9(7–10) per stem, undivided or irregularly pinnate, plicate, bases of blades running diagonally into the rachis; sheaths 18.9(15.0–23.5) cm long; petioles 27.4(12.0–41.5) cm long, drying green or yellowish; rachis 31.6(21.0–57.0) cm long, 3.4(1.8–5.0) mm in diameter; veins raised and rectangular in cross-section adaxially; pinnae 3(1–7) per side of rachis; basal pinna 32.6(28.0–40.0) cm long, 3.4(1.3–6.5) cm wide, forming an angle of 28(13– 43)° with the rachis; apical pinna 29.3(18.6–39.0) cm long, 7.2(5.5–8.6) cm wide, forming an angle of 17(10– 25)° with the rachis. Inflorescences unbranched; prophylls ribbed with elongate, unbranched fibers, tubular, narrow, elongate, closely sheathing the peduncle, more or less persistent; prophylls 29.9(16.5–38.0) cm long, not short and asymmetrically apiculate, the surfaces not ridged, without unequally wide ridges; peduncular bracts absent; peduncles 68.5(55.5–81.0) cm long, 2.3(1.6–3.2) mm in diameter; rachillae 1, 16.2(11.5–23.5) cm long, 3.5(2.5–4.6) 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 apiculate and lobed before anthesis, tearing in the center after anthesis, 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 almost directly onto the filament apices, the connectives bifid but scarcely developed; anthers short and curled over at anthesis; non-fertilized pistillate flowers persistent after anthesis; staminodial tubes crenulate or shallowly lobed at the apex, those of non-fertilized pistillate flowers not projecting and persistent after anthesis; fruits 7.3(6.3–8.3) mm long, 5.2(4.5–5.8) mm in diameter, the bases with a prominent, asymmetric 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 without operculum, smooth, without pores.

Distribution and habitat:— From 8°45’– 9°47’N and 82°43’– 83°41’W in Costa Rica and just reaching Panama at 1781(1250–2315) m elevation in montane rainforest ( Fig. 40 ).

Taxonomic notes:— Geonoma talamancana is a member of a group of high elevation, Andean species (the G. undata clade, also including G. lehmannii , G. orbignyana , G. trigona , and G. undata ). It is very similar to G. lehmannii subsp. corrugata , differing only in its lack of a peduncular bract.

Subspecific variation:— Two traits (stem branching, leaf division) vary within this species. There is geographic discontinuity but too few specimens to test for differences. The specimens from the western part of the range occur at lower elevations (mean of 1460 m versus 2054 m) and have fewer pinnae.

Figures

FIGURE 40. Distribution maps of Geonoma stricta subsp. quibdoensis, G. stricta subsp. submontana, G. talamancana, and G. tenuissima.