Difference between revisions of "Geonoma longivaginata"

Taxonomic notes: - Geonoma longivaginata is a member of a group of three species within the G. stricta clade, the other two being G. divisa and G. ferruginea. It differs from G. divisa in its crenulate or shallowly lobed staminodial tube; and from G. ferruginea in its rachillae with short, transverse ridges.

Subspecific variation: - Two traits vary within this species (stem branching, adaxial veins). The species is distributed in Panama and Costa Rica and just reaches Nicaragua. It is divided into several disjunct populations. The state distribution of one trait (adaxial veins) together with geography suggest several subgroups. Specimens with raised adaxial veins occur in Panama (San Blas) and are treated as a separate subgroup. Specimens with non-raised adaxial veins occur in five areas: Atlantic slope in Costa Rica and adjacent Nicaragua and Panama; Pacific slope in Costa Rica; El Copé, Llano Grande, and Cerro Tife in Panama; El Valle in Panama; and the Santa Rita Ridge in Panama. Specimens from the Atlantic and Pacific slopes in Costa Rica do not differ significantly from each other in any quantitative variable, and these are treated as one subgroup. There are thus five potential subgroups, but there are only three specimens of one of these, from the Santa Rita Ridge in Panama, too few to test for differences. Four potential subgroups are tested for differences. ANOVA shows that for pair wise comparison probabilities, all variables except leaf number and fruit length differ significantly (P <0.05) between at least one pair of subgroups, although no variable differs amongst all four subgroups. Based on these results and geography, the four subgroups are recognized as subspecies. Specimens from Santa Rita Ridge in Panama are included with those from the Atlantic and Pacific slopes in Costa Rica (see below) (subspp. copensis, longivaginata, sanblasensis, vallensis). (Henderson, A.J. (2011) A revision of Geonoma. Phytotaxa 17: 1-271.)/Palmweb.

1.) Geonoma longivaginata subsp. copensis; Panamá. From 8°37-8°47'N and 80°28-80°39'W in central Panama (Cerro Tife, El Copé, Llano Grande) at 721 (200-1200) m elevation in lowland to montane tropical rainforest. Leaves veins not raised or slightly raised and triangular in cross-section adaxially; rachis 23.5(16.5-30.0) cm long. Inflorescences peduncles 5.2(3.8?7.5) cm long; rachillae 3 (2-4), 17.0 (14.0-20.5) cm long.

2.) Geonoma longivaginata subsp. longivaginata; Costa Rica, Nicaragua, and Panamá. From 8°40-11°30'N and 79°40-84°25'W in Nicaragua, Costa Rica (Atlantic and Pacific slopes) and Panama at 185(5-1000) m elevation in lowland tropical rainforest. Leaves veins not raised or slightly raised and triangular in cross-section adaxially; rachis 67.2(42.0-101.0) cm long. Inflorescences peduncles 9.5 (5.0-16.0) cm long; rachillae 7 (4?18), 25.7 (10.0-42.0) cm long. The outlying specimens from the Santa Rita Ridge in Panama (de Nevers 10649, Hammel 14498, Porter 4741) have fewer pinnae, wider basal pinnae, and fewer rachillae than the others, but there are too few specimens to test for differences. Three specimens (Cooper 493, de Nevers 6864, Lewis2162) from western Panama are smaller than others and resemble Geonoma deversa subsp. deversa (although this subspecies does not occur in the area). They may be hybrids and are not included in the above description and analysis.

3.) Geonoma longivaginata subsp. sanblasensis; Panamá. Leaves veins raised and rectangular in cross-section adaxially; rachis 52.8 (42.0-64.0) cm long. Inflorescences peduncles 11.4 (8.0-14.0) cm long; rachillae 6 (4-8), 27.7 (22.3-37.0) cm long.

4.) Geonoma longivaginata subsp. vallensis; Panamá. From 8°37-8°40'N and 80°05-80°12'W in central Panama (El Valle) at 917 (880-950) m elevation in lowland tropical rainforest. Leaves veins not raised or slightly raised and triangular in cross-section adaxially; rachis 28.1(20.5-37.5) cm long. Inflorescences peduncles 9.2 (7.4-12.1) cm long rachillae 4 (3-5), 18.8 (15.4-25.2) cm long. (Henderson, A.J. (2011) A revision of Geonoma. Phytotaxa 17: 1-271.)

A monoecious species from Mexico to South America, it is fairly difficult and relatively slow growing. It suckers but not profusely so and leaves are very variable from finely pinnate to very broad leaflets to a mixture of both. The oldest plants growing here (Maria's Palmetum, Nth Qld) are about nine years old and have grown to 2 metres in height with trunks of about 3 cm diameter. But, so far, have shown no signs of flowering. New leaves are always very red and may show signs of cold damage in winter.

This smallish, clustering species has thin, cane-like stems, usually no more than 2 m (7 ft) tall, and dainty leaves with sickle-shaped leaflets. The infructescences are thick and red and particularly eye-catching. It is native to rainforest in Costa Rica and Panama and an easy and rewarding understorey plant for tropical and warm subtropical areas. (RPS.com)