Geonoma schizocarpa Henderson, 2011

Henderson, Andrew, 2011, A revision of Geonoma (Arecaceae), Phytotaxa 17, pp. 1-271 : 135-137

55. Geonoma schizocarpa Henderson , sp. nov. (Appendix IV, Plates 58 & 59)

A speciebus affinibus crusta fructuum profunde scindens differt.

Type: PERU. Amazonas: al lado de Huampami, 18 July 1974, R. Kyap 1212 (holotype MO!).

Plants 2.2(1.0–5.0) m tall; stem height no data, 2.8 cm in diameter, branching no data, not cane-like; internodes 0.3 cm long, not scaly. Leaves irregularly pinnate, not plicate, bases of blades running diagonally into the rachis; sheaths 12.0 cm long; petioles drying green or yellowish; rachis 90.0(88.0–92.0) cm long, 7.9(6.2–8.7) mm in diameter; veins raised and rectangular in cross-section adaxially; pinnae 14 per side of rachis; basal pinna 34.0 cm long, 1.2(0.8–1.6) cm wide, forming an angle of 67(51–82)° with the rachis; apical pinna 20.0 cm long, 4.9(2.8–6.5) cm, forming an angle of 31(30–33)° 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 14.5 cm long, not short and asymmetrically apiculate, the surfaces not ridged, without unequally wide ridges; peduncular bracts length no data, well-developed, inserted 0.6 cm above the prophyll; peduncles 93.0 cm long, 5.7(4.6–7.2) mm in diameter; rachillae 1, 22.6(15.5–36.0) cm long, 9.8(7.7–11.5) 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 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 flowers persistent post-anthesis or deciduous post-anthesis; staminate and pistillate petals not emergent, not valvate throughout; stamens 6; thecae not diverging at anthesis, inserted onto well-developed, non-split, jointed connectives, alternately long and short; anthers short at anthesis, remaining straight and parallel; nonfertilized pistillate flowers deciduous after anthesis; staminodial tubes lobed at the apex, the lobes spreading at anthesis, acuminate, those of non-fertilized pistillate flowers not projecting and persistent after anthesis; fruits 14.0(12.3–15.5) mm long, 8.9(8.6–9.3) mm in diameter, the bases without a prominent stipe, the apices not conical, the surfaces splitting deeply and longitudinally at maturity to reveal mesocarp with dense layer of radial fibers, without fibers emerging, not bumpy, not apiculate; locular epidermis with operculum, smooth, without pores.

Distribution and habitat:— From 4°15’– 4°30’S and 78°10’– 78°30’W in Peru (Amazonas) at 225 m elevation in lowland rainforest ( Fig. 37 ).

Taxonomic notes:— Geonoma schizocarpa is a member of the G. macrostachys clade. Within this it is most closely related to G. macrostachys , G. multisecta , G. paradoxa , and G. poiteauana . It differs from these in its fruits surfaces which split deeply and longitudinally at maturity to reveal mesocarp with a dense layer of radial fibers.

Subspecific variation:— One trait (staminate flower persistence) varies within this species. Two of 10 specimens have deciduous staminate flowers.

Figures

FIGURE 37. Distribution maps of Geonoma schizocarpa, G. schottiana, G. scoparia, and G. simplicifrons.