Geonoma triandra Wessels Boer 1968
Creators: name: Henderson, Andrew
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Arecales
Arecaceae
Geonoma
Geonoma triandra

description: 63. Geonoma triandra (Burret) Wessels Boer (1968: 85). Kalbreyera triandra Burret (1930a: 143). Type: COLOMBIA. Antioquia: Murrí, 1000 m, 21 July 1880, W. Kalbreyer 1829 (holotype B, destroyed). Neotype (here designated): COLOMBIA. Antioquia: Mun. Mutatá, Hacienda Mocarí, carretera Mutatá-Pavarando, 180 m, 1 May 1987, R. Fonnegra, F. Roldán, J. Betancur, & A. Betancur 2002 (neotype NY!).
Plants 2.8(2.0–3.5) m tall; stems 2.5 m tall, 0.7(0.5–1.4) cm in diameter, clustered, cane-like; internodes 1.3(0.7–2.4) cm long, yellowish and smooth. Leaves 10(8–11) per stem, undivided or irregularly pinnate, not plicate, bases of blades running diagonally into the rachis; sheaths 6.1(4.7–8.0) cm long; petioles 9.9(4.5– 14.7) cm long, drying green or yellowish; rachis 29.8(20.8–37.5) cm long, 2.6(1.6–3.6) mm in diameter; veins not raised or slightly raised and triangular in cross-section adaxially; pinnae 2(1–3) per side of rachis; basal pinna 19.1(14.0–30.0) cm long, 6.8(3.8–14.5) cm wide, forming an angle of 36(20–57)° with the rachis; apical pinna 13.9(8.5–18.0) cm long, 10.3(7.0–12.7) cm wide, forming an angle of 36(28–46)° with the rachis. Inflorescences branched 2–3 orders; prophylls and peduncular bracts not ribbed with elongate, unbranched fibers, flattened, persistent; prophylls 13.7(5.5–27.0) cm long, not short and asymmetrically apiculate, the surfaces not ridged, without unequally wide ridges; peduncular bracts 1.8(0.1–6.0) cm long, vestigial, inserted 3.7(0.5–7.3) cm above the prophyll; peduncles 15.2(6.5–28.5) cm long, 3.1(2.1–4.5) mm in diameter; rachillae 40(21–75), 10.0(6.0–15.0) cm long, 1.1(0.8–1.8) 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 decussately arranged throughout the rachillae, the groups of pits closely spaced, 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 well-developed; staminate and pistillate petals not emergent, not valvate throughout; staminate flowers deciduous after anthesis; stamens 3; 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 non-fertilized pistillate flowers not projecting and persistent after anthesis; fruits 6.8(6.0–7.4) mm long, 5.6(4.8–6.1) 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 without operculum, smooth, without pores.
Distribution and habitat:— From 0°48’– 8°05’N and 76°00’– 78°44’W in eastern Panama, western Colombia, and northwestern Ecuador at 233(45–1250) m elevation in lowland or montane rainforest (Fig. 41).
Taxonomic notes:— Geonoma triandra is one of only two species of Geonoma with staminate flowers with three stamens; G. hollinensis is the other. Lacking staminate flowers, it can be recognized by its vestigial peduncular bracts and decussately arranged flower pits.
Subspecific variation:— One trait (leaf division) varies within this species. There is geographic discontinuity and specimens come from several disjunct areas. However, there are too few specimens to test for differences, and the gaps may be artifacts of insufficient collecting.
description: Published as part of Henderson, Andrew, 2011, A revision of Geonoma (Arecaceae), pp. 1-271 in Phytotaxa 17 on page 150, DOI: 10.11646/phytotaxa.17.1, http://zenodo.org/record/3538362