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 8. Geonoma camana Trail (1876: 324) . Taenianthera camana (Trail) Burret (1930a: 270) Type: BRAZIL . Amazonas: San Antonia da Boa Vista, Rio Javari, 4 December 1874 , J . Trail 977/CLXXXII ( holotype K n.v. , isotype P !). Geonoma lagesiana Dammer (1907: 121) . Taenianthera lagesiana (Dammer) Burret (1930a: 270) . Type: BRAZIL . Amazonas: Rio Juruá, Juruá–mirim, August 1901 , E. Ule 5745 ( holotype not known, isotype MG!). Plants 2.0(0.8–4.0) m tall; stems 0.5(0.1–1.3) m tall, 2.3(1.7–2.8) cm in diameter, solitary, not cane-like; internodes 0.6(0.5–0.6) cm long, not scaly. Leaves 9(5–14) per stem, irregularly pinnate or regularly pinnate and the pinnae with 1 main vein only, not plicate, the bases of blades running diagonally into the rachis; sheaths 19.2(5.0–50.0) cm long; petioles 71.0(24.0–140.0) cm long, drying green or yellowish; rachis 83.1(46.0–137.0) cm long, 5.7(2.8–9.4) mm in diameter; veins not raised or slightly raised and triangular in cross-section adaxially; pinnae 17(2–38) per side of rachis; basal pinna 30.5(13.4–57.0) cm long, 4.3(0.3– 24.0) cm wide, forming an angle of 53(20–95)° with the rachis; apical pinna 19.9(6.8–36.0) cm long, 12.6(1.7–31.0) cm wide, forming an angle of 44(31–60)° 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 11.6(4.5–25.5) cm long, not short and asymmetrically apiculate, the surfaces not ridged, without unequally wide ridges; peduncular bracts 20.4(12.0–28.5) cm long, well-developed, inserted 2.7(0.6–4.4) cm above the prophyll; peduncles 44.9(21.5– 100.0) cm long, 3.9(2.1–5.8) mm in diameter; rachillae 1, 23.8(10.5–36.0) cm long, 5.8(2.8–8.3) 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 pits 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 flowers not projecting and persistent after anthesis; fruits 10.7(8.7–13.5) mm long, 6.9(6.0–8.9) 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, without pores. Distribution and habitat:— From 0°08’– 13°21’S and 68°46’– 78°19’W in the western Amazon region of Colombia , Ecuador , Peru , and Brazil at 210(87–850) m elevation in lowland rainforest ( Fig. 11 ). Taxonomic notes:— In previous treatments (e.g., Henderson et al., 1995 ), Geonoma camana was said to be characterized by its thick, smooth pinnae with conspicuous, submarginal veins. In the present work, these potential characters have been found to be inconsistent and difficult to score, and are therefore not used. Geonoma camana differs from similar species in the G. macrostachys clade ( G. chlamydostachys , G. chococola , G. deneversii , and G. maxima ) in its fruit surfaces not splitting, and locular epidermis with operculum and without pores. Subspecific variation:— No traits vary within this species. There is a gap in the distribution of G. camana , between Ecuador and adjacent Colombia and Peru in the west, and Colombia , Peru , and Brazil in the east. However, the intervening area is poorly collected for palms, and this gap may be an artifact of insufficient collecting. There is geographical variation in this species. Regression shows there are significant associations between longitude and two plant, seven leaf, and three inflorescence variables. Squared multiple R for the regression of plant height on longitude is 0.36, stem height 0.24, petiole length 0.40, rachis width 0.54, basal pinna length 0.31, basal pinna angle 0.12, apical pinna length 0.50, apical pinna width 0.10, apical pinna angle 0.19, peduncle width 0.25, rachilla length 0.19, and rachilla width 0.18. From east to west, specimens become smaller. In particular, there is a change in leaf size and shape, from specimens in the east having longer basal and apical pinnae with narrower angles, to those in the west shorter basal and apical pinnae with wider angles. Four specimens from Acre , Brazil ( Ferreira 125, 136, 163, 165) are much smaller than others and may represent hybrids between G. camana and G. macrostachys . Other specimens from Loreto , Peru ( Balick 1131 ) and from Amazonas, Brazil ( Pardini 45 ) also appear intermediate between these two species. These potential hybrids are not included in the above description or analysis.