A revision of Geonoma (Arecaceae) Author Henderson, Andrew text Phytotaxa 2011 2011-02-18 17 1 271 journal article 24911 10.11646/phytotaxa.17.1 65962ba7-eec1-40e7-aed6-cef94e99ca39 1179-3163 3538362 13. Geonoma congesta Wendland ex Spruce (1871: 112) . Type: COSTA RICA . Heredia : Río Sarapiquí, between Pedegral and San Miguel, 1857, H. Wendland s.n. ( holotype K!). Plants 3.4(1.5–6.0) m tall; stems 4.1(1.0–8.0) m tall, 1.6(1.0–2.7) cm in diameter, solitary or clustered, canelike; internodes 2.0(0.9–5.5) cm long, yellowish and smooth. Leaves 10(6–13) per stem, undivided or irregularly pinnate, not plicate, bases of blades running diagonally into the rachis; sheaths 23.2(15.5–27.0) cm long; petioles 18.7(5.5–51.0) cm long, drying green or yellowish; rachis 66.1(38.8–132.0) cm long, 5.1(2.4– 15.2) mm in diameter; veins raised and rectangular in cross-section adaxially; pinnae 4(1–24) per side of rachis; basal pinna 59.2(33.0–82.0) cm long, 18.0(4.5–35.5) cm wide, forming an angle of 25(15–38)° with the rachis; apical pinna 34.9(21.7–48.0) cm long, 20.7(7.1–42.0) cm wide, forming an angle of 26(20–32)° with the rachis. Inflorescences branched 1–3 orders; prophylls and peduncular bracts not ribbed with elongate, unbranched fibers, flattened, deciduous or persistent; prophylls 15.9(6.0–29.7) cm long, not short and asymmetrically apiculate, the surfaces ridged with close, equal, parallel, non-dividing ridges, scarcely tomentose between the ridges, without unequally wide ridges; peduncular bracts 16.5(13.0–26.5) cm long, well-developed, inserted 0.6(0.3–1.0) cm above the prophyll; peduncles 7.8(4.2–13.0) cm long, 6.2(3.4–9.8) mm in diameter; rachillae 9(3–16), 12.8(6.0–23.0) cm long, 5.8(4.1–7.2) 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 without a central notch before 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 at the apex, those of non-fertilized flowers projecting and persistent after anthesis; fruits 12.4(9.7– 15.2) mm long, 9.8(8.1–11.7) mm in diameter, the bases with a prominent, asymmetric stipe, the apices not conical, the surfaces not splitting at maturity, with fibers emerging, not bumpy, not apiculate; locular epidermis with operculum, smooth, with pores. Taxonomic notes:— Henderson et al. (1995) included Geonoma calyptrogynoidea as a synonym of G. congesta –see notes under that species. Subspecific variation:— No trait apart from stem branching and leaf division varies within this species. There is geographic discontinuity and there is an isolated population on the Pacific slope of Costa Rica (Osa Peninsula and adjacent areas). There are thus two potential subgroups. Specimens from Osa differ significantly from other specimens in 10 variables (plant height, rachis length, rachis width, number of pinnae, apical pinna length, peduncle width, rachillae length, rachillae width, number of rachillae, fruit diameter)( t -test, P <0.05). Specimens from Osa have larger mean values for all these variables. Based on these results, and geographic discontinuity, the two subgroups are recognized as subspecies (subspp. congesta , osensis ). Key to the subspecies of G. congesta 1 - Rachillae 11.9(6.0–21.5) cm long; Honduras , Nicaragua , Costa Rica (excluding Osa Peninsula and adjacent areas), and western and central Panama ............................................................................................................ subsp. congesta Rachillae 19.1(15.0–23.0) cm long; Osa Peninsula and adjacent areas on the Pacific slope in Costa Rica .................. ................................................................................................................................................................. subsp. osensis