Geonoma elegans Martius 1826
Creators: name: Henderson, Andrew
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Arecales
Arecaceae
Geonoma
Geonoma elegans

description: 19. Geonoma elegans Martius (1826: 144). Type: BRAZIL. Rio de Janeiro: no locality, no date, H. Schott s. n. (holotype, not known, presumed lost). Neotype (here designated): BRAZIL. Rio de Janeiro: Maciço da Tijuca, Reserva Florestal da FEEMA, 550 m, 17 October 1977, P. Maas & P. Carauta 3285 (neotype NY!).
Geonoma elegans var. robusta Drude (1882: 506). Type: BRAZIL. Rio de Janeiro: Barrière des Orgnes, 12 May 1877, A. Glaziou 9018 (holotype BR!, isotypes FI!, NY!, P!).
Geonoma bifurca Drude & Wendland in Drude (1882: 504). Type: BRAZIL. Rio de Janeiro: no locality, no date, L. Riedel 732 (holotype M!, isotypes BR!, C, n.v., F!, P!,).
Plants 1.9(1.0–3.0) m tall; stems 1.9(0.8–3.0) m tall, 0.7(0.4–1.0) cm in diameter, clustered, cane-like; internodes 1.5(0.6–3.0) cm long, yellowish and smooth. Leaves 9(8–10) per stem, undivided or irregularly pinnate, rarely regularly pinnate and the pinnae with 1 main vein only, not plicate, bases of blades running diagonally into the rachis; sheaths 8.2(4.5–13.0) cm long; petioles 12.0(3.0–29.0) cm long, drying green or yellowish; rachis 26.0(13.5–45.0) cm long, 2.5(1.3–4.3) mm in diameter; veins not raised or slightly raised and triangular in cross-section adaxially; pinnae 3(1–14) per side of rachis; basal pinna 22.4(15.5–34.5) cm long, 4.9(0.2–8.2) cm wide, forming an angle of 33(8–52)° with the rachis; apical pinna 14.1(8.0–26.5) cm long, 9.4(4.0–15.3) cm wide, forming an angle of 29(20–40)° 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 15.2(8.0–28.5) cm long, not short and asymmetrically apiculate, the surfaces without ridges; peduncular bracts 18.5(8.0–285.0) cm long, welldeveloped, inserted 6.2(1.7–11.0) cm above the prophyll; peduncles 26.2(10.0–45.06) cm long, 2.5(1.3–4.8) mm in diameter; rachillae 1, 17.6(3.5–28.0) cm long, 4.0(1.9–8.0) 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 deciduous after anthesis; staminodial tubes crenulate or shallowly lobed at the apex, those of non-fertilized flowers not projecting and persistent after anthesis; fruits 9.5(7.6–12.3) mm long, 7.2(5.8–9.2) mm in diameter, the bases with a prominent, asymmetric stipe, the apices conical with rounded apices, the surfaces not splitting at maturity, without fibers emerging, not bumpy, not apiculate; locular epidermis without operculum, smooth or sculpted and then usually also with a raised, meridional ridge, without pores.
Distribution and habitat:— From 16°01’– 26°55’S and 39°22’– 49°49’W in the Atlantic Coastal Forest of Brazil (southern Bahia and Minas Gerais to Santa Catarina) at 265(2–800) m elevation in lowland rainforest (Fig. 17).
Taxonomic notes:— Wessels Boer (1968) stated that the type specimen of G. elegans was not at either M or R, and it has not been seen at either herbaria, or any other, in the present study. A neotype is therefore designated. Geonoma elegans is the first species dealt with here in a group of species from the Atlantic Coastal Forest and adjacent Cerrado of Brazil (the G. schottiana clade, also including G. pauciflora, G. pohliana, and G. schottiana). Although the clade is well-supported, all constituent species are extremely variable internally. Geonoma elegans differs from other species in the group by its prophylls and peduncular bracts which are ribbed with elongate, unbranched fibers, and both bracts are tubular, narrow, elongate, closely sheathing the peduncle, and more or less persistent
Subspecific variation:— Two traits vary within this species (leaf division, locular epidermis sculpting). There is no geographic discontinuity, except for an outlying specimen from Minas Gerais. There are many missing data for locular epidermis sculpting, and leaf division is not consistent, so these traits are not used to divide specimens. Because of this, no subspecies are recognized. However, G. elegans is a variable species.
A specimen (Fiaschi 3154) from Rio de Janeiro has pinnate leaves with 14 pinnae per side of the rachis (versus 1–6 for other specimens) and the pinnae have 1 main vein only (pinnate morphotype).
Three specimens (Riedel 732 (type of G. bifurca), Mello–Silva 844, Martinelli 13314) from eastern part of the Serra do Mar in Rio de Janeiro have narrow, undivided leaves (bifurca morphotype).
Six specimens (Bausen 129, Demuner 4032, Fernandes 1833, 1837, Folli 1660, Kollmann 4170) from Espírito Santo have broad, undivided leaves (broad leaf morphotype). They occur on the Serra do Mar at 400– 700 m elevation.
Five specimens (Fernandes 3095, 3103, 3290, Kollmann 6324, 9321) from Espírito Santo have thicker rachillae than usual (thick rachillae morphotype). They occur on the Serra do Mar at 550–800 m elevation.
Specimens from lower elevations (30–400) in Espírito Santo and southern Bahia, including the outlier from Minas Gerais, are smaller than usual (small morphotype). They have smaller leaves and these are mostly undivided. Two of these (Hatschbach 47799, Lombardi 5156) have non-sculpted endocarps (as opposed to the more common sculpted). There is no overlap between the ranges of the small morphotype of G. elegans and G. pauciflora, but specimens of the small morphotype resemble some of those of the pinnate-branched morphotype of G. pauciflora and there may be a hybrid zone in the region of southern Bahia and Espírito Santo between G. elegans and G. pauciflora.
Specimens from Rio de Janeiro to Santa Catarina are less variable and typically have three pinnae per side of the rachis. A few specimens from São Paulo (Kirizawa 935, Leitão Filho 33102, 34584) have undivided leaves. Two specimens from the southern margin of the range, in Santa Catarina (Lourteig 2374, Smith 5712) have non-sculpted endocarps (as opposed to the more common sculpted).
description: Published as part of Henderson, Andrew, 2011, A revision of Geonoma (Arecaceae), pp. 1-271 in Phytotaxa 17 on pages 68-70, DOI: 10.11646/phytotaxa.17.1, http://zenodo.org/record/3538362