Geonoma scoparia Grayum & Nevers, Principes 32: 111 (1988)

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Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)
Costa Ricapresent (World Checklist of Arecaceae)B
From 8°33-8°45'N and 83°06-83°33'W in Costa Rica on the Osa Peninsula and adjacent areas at 245(100-350) m elevation in lowland rainforest. (Henderson, A.J. (2011) A revision of Geonoma. Phytotaxa 17: 1-271.)A

Discussion

  • Taxonomic notes: - Geonoma scoparia is closely related to G. mooreana, the two species differing from related species (the G. lanata clade) in their proximal and distal lips joined to form a raised cupule. Geonoma scoparia differs from G. mooreana in its solitary stems and internodes covered with dense, brown scales.

    Subspecific variation: - No trait varies within this species nor is there any geographic disjunction. (Henderson, A.J. (2011) A revision of Geonoma. Phytotaxa 17: 1-271.)A

Description

  • Plants 2.5(2.0-3.0) m tall; stems 2.5(2.0-3.0) m tall, 1.1(0.8-1.5) cm in diameter, solitary, cane-like; internodes 1.5(0.8-2.5) cm long, covered with dense, brown scales. Leaves 16(12-19) per stem, irregularly pinnate, not plicate, bases of blades running diagonally into the rachis; sheaths 10.8(9.5-14.0) cm long; petioles 24.1(18.0-35.5) cm long, drying green or yellowish; rachis 30.0(23.2-33.5) cm long, 2.3(1.9-2.6) mm in diameter; veins raised and rectangular in cross-section adaxially; pinnae 3 per side of rachis; basal pinna 23.7(20.5-30.0) cm long, 2.0(1.0-3.5) cm wide, forming an angle of 72(65-78)° with the rachis; apical pinna 14.0(11.5-16.5) cm long, 7.2(5.5-9.2) cm wide, forming an angle of 38(34-44)° with the rachis. Inflorescences branched 4 orders; prophylls and peduncular bracts not ribbed with elongate, unbranched fibers, flattened, deciduous; prophylls 7.0(6.5-7.3) cm long, short, asymmetrically apiculate, the margins curved around the stem, the surfaces flat with dense, felty, brown tomentum, prophyll equal to and early deciduous with the peduncular bract, the surfaces not ridged, without unequally wide ridges; peduncular bracts 7.0 cm long, well-developed, inserted 0.3(0.2-0.6) cm above the prophyll; peduncles 2.8(2.5-3.2) cm long, 3.3(3.1-3.6) mm in diameter; rachillae 112(85-138), 9.1(6.0-13.5) cm long, 0.6(0.4-1.0) mm in diameter, the surfaces without spiky, fibrous projections or ridges, drying brown, with faint to pronounced, short, transverse ridges, filiform with extended narrowed sections between the flower pits; flower pits alternately arranged (sometimes distorted by twisting and contracting of rachillae), glabrous internally; proximal lips without a central notch before anthesis, not recurved after anthesis, not hood-shaped; proximal and distal lips drying the same color as the rachillae, joined to form a raised cupule, the margins not overlapping; 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 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 6.0(5.8-6.1) mm long, 4.7 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. (Henderson, A.J. (2011) A revision of Geonoma. Phytotaxa 17: 1-271.)A