Geonoma poeppigiana Martius 1843
Creators: name: Henderson, Andrew
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Arecales
Arecaceae
Geonoma
Geonoma poeppigiana

description: 50. Geonoma poeppigiana Martius (1843: 35). Type: PERU. Loreto: Yurimaguas, February 1891, E. Poeppig 2295 (holotype M!).
Plants 1.9(1.0–4.0) m tall; stems 0.9(0.1–4.0) m tall, 1.6(1.2–2.0) cm in diameter, solitary, not cane-like or cane-like; internodes 0.5(0.3–0.8) cm long, yellowish and smooth, or, if short and congested, not scaly. Leaves 11(4–16) per stem, undivided or irregularly pinnate, not plicate, bases of blades running diagonally into the rachis; sheaths 16.9(10.0–25.0) cm long; petioles 49.8(30.0–100.0) cm long, drying green or yellowish; rachis 58.4(36.5–100.0) cm long, 4.8(2.3–7.9) mm in diameter; veins raised and rectangular in cross-section adaxially or not raised or slightly raised and triangular in cross-section adaxially; pinnae 4(1–11) per side of rachis; basal pinna 36.8(13.5–60.5) cm long, 4.9(0.5–15.3) cm wide, forming an angle of 40(12–90)° with the rachis; apical pinna 30.0(10.3–45.0) cm long, 15.1(3.3–24.5) cm long, forming an angle of 28(20–45)° with the rachis. Inflorescences unbranched or branched 1 order; prophylls and peduncular bracts not ribbed with elongate, unbranched fibers, flattened (if tubular, narrow, and elongate then not ribbed), deciduous or persistent; prophylls 27.8(15.5–40.0) cm long, not short and asymmetrically apiculate, the surfaces not ridged, without unequally wide ridges; peduncular bracts 25.8(21.0–38.0) cm long, well-developed, inserted 2.1(0.7– 4.7) cm above the prophyll; peduncles 56.1(28.0–89.0) cm long, 5.6(1.9–11.1) mm in diameter; rachillae 4(1– 10), 25.8(9.7–40.0) cm long, 4.2(1.9–7.1) 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, 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 a scarcely raised rim; staminate and pistillate petals not emergent, not valvate throughout; staminate flowers deciduous after anthesis; stamens 6; thecae diverging at anthesis, inserted onto bifid and well-developed, non-jointed connectives; 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 7.2(6.4–8.4) mm long, 5.6(4.6–6.6) 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 or locular epidermis sculpted and then usually also with a raised, meridional ridge; locular epidermis without pores.
Distribution and habitat:— From 0°40’– 11°50’S and 70°09’– 78°30’W in the sub-Andean and western Amazon regions of Colombia, Ecuador, Peru, and Brazil, with an outlier in southern Peru, at 288(110–980) m elevation in lowland tropical rainforest (Fig. 33).
Taxonomic notes:— Wessels Boer (1968) considered that Geonoma poeppigiana had the inflorescences covered with a distinctive brownish-gray tomentum. Some specimens have this but most do not, and it appears to have little taxonomic significance. Geonoma poeppigiana appears most similar to G. brongniartii, G. longipedunculata, and G. sanmartinensis. It differs from these in its thecae which diverge at anthesis and are inserted onto bifid and well-developed, non-jointed connectives.
Subspecific variation:— Five traits (stem type, leaf division, adaxial veins, inflorescence branching, locular epidermis sculpting) vary within this species. There is geographic discontinuity and there are several isolated populations. Leaving aside stem type and locular epidermis sculpting, for which there are few data, and also leaf division, there is no correspondence between geography and variation in adaxial veins and inflorescence branching. Specimens non-raised adaxial veins are from scattered localities and seem to be associated with undivided leaves or leaves with fewer pinnae. However, this trait is difficult to score in this species. Specimens with unbranched inflorescences occur in two areas but are intermixed with similar specimens with branched inflorescences. Because of this inconsistency, no subspecies are recognized in this species. However, there is much local variation.
Specimens from the Colombian and Brazilian Amazon and from the region around Iquitos in Peru (Maynas Province) are similar. They have mostly undivided leaves or 2–5 pinnae per side of the rachis with narrow basal angles and the adaxial veins are not or scarcely raised, with some exceptions (e.g., McDaniel 27585). Specimens from nearby Requena Province have more pinnae (2–8) and more pronounced adaxial veins.
There is a gap in the distribution of G. poeppigiana between the region around Iquitos in Peru (Maynas and Requena Provinces) and Ecuador and sub-Andean Peru. Despite this gap, there appears to be geographical variation in G. poeppigiana. Regression shows there are significant associations between longitude and eight leaf and three inflorescence variables. Squared multiple R for the regression of leaf number on longitude is 0.50, number of pinnae 0.25, basal pinna length 0.75, basal pinna width 0.31, basal pinna angle 0.33, apical pinna length 0.29, apical pinna width 0.49, apical pinna angle 0.52, peduncle width 0.26, rachilla length 0.27, and number of rachillae 0.21. In particular, there is a change in leaf shape, with plants in the east having leaves with fewer pinnae (often undivided), longer and narrower basal and apical pinnae with narrower angles. This kind of geographical variation also occurs in Geonoma brongniartii and G. camana.
Specimens from the Ecuadorian Amazon and adjacent Peru also have more pinnae (5–10) per side of the rachis and pronounced adaxial veins.
Specimens from Peru (Amazonas) are extremely variable. There are several specimens which resemble those from the Ecuadorian Amazon, but others with unbranched inflorescences. For example, at the same locality in Bagua Province, there are two specimens (Quipuscoa 340, Rodríguez 584) with leaves with 11, narrow pinnae per side of the rachis and inflorescences with 4–5 rachillae, these 11.5–14.7 cm long and 3.0– 3.6 mm wide; and two other specimens (Vásquez 19645, 23925) with three, broad pinnae per side of the rachis and large, unbranched inflorescences with the rachilla 31.5–32.5 cm long and 6.5–6.6 mm wide.
Specimens from northern San Martín and adjacent Loreto in Peru are typical, although one (Moore 8530) from Yurimaguas is considerably larger than the others, and is reported to have a stem to 4 m tall.
Specimens from southern San Martín, all from the same area near Tocache Nuevo are also very diverse. There are several typical specimens, but one (Plowman 5937) has a undivided leaf with non-raised veins and branched inflorescence, another (Schunke 10804) has a undivided leaf with raised veins and unbranched inflorescence, two (Plowman 11461, Schunke 7612) have much smaller inflorescences and Schunke 7612 also has a much smaller leaf, and others have the more common leaf type but unbranched inflorescences (Plowman 11677, Schunke 6615).
There is an outlying specimen in Madre de Dios. Three other specimens (Moreno 126, 305, Henderson 1636) from the border area between Peru and Bolivia, are not included in the above analyses or in the species description. These have branched inflorescences and one has rachillae surfaces with faint to pronounced, short, transverse ridges. These three specimens may represent hybrids between G. poeppigiana and another species.
description: Published as part of Henderson, Andrew, 2011, A revision of Geonoma (Arecaceae), pp. 1-271 in Phytotaxa 17 on pages 123-125, DOI: 10.11646/phytotaxa.17.1, http://zenodo.org/record/3538362