Geonoma pohliana Mart., Hist. Nat. Palm. 2: 142 (1826)

Primary tabs

http://media.e-taxonomy.eu/palmae/photos/palm_tc_89537_2.jpg

Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)

Discussion

  • Taxonomic notes: - Geonoma pohliana is a member of a group of species from the Atlantic Coastal Forest and adjacent Cerrado (the G. schottiana clade, also including G. elegans, G. pauciflora, and G. schottiana). Although the group is well-supported, all constituent species are extremely variable internally. Geonoma pohliana differs from other species in the group by its prophyll surfaces which are ridged and densely tomentose with widely to closely spaced, unequally wide ridges, these often dividing from and rejoining other ridges. The variation within this species, both in qualitative traits, quantitative variables, and geography allow separation into various subspecies, as described below.

    Subspecific variation: - Five traits vary within this species (stem branching, stem type, inflorescence branching, rachillae narrowing, lip color). Leaving aside stem branching and stem type, for which there are few data, the remaining three traits divide the specimens into three subgroups. However, lip color is difficult to score in this species. There is little geographic discontinuity, and the specimens are widely distributed in the Atlantic Coastal Forest and Cerrado regions of Brazil and just reach adjacent countries. These three subgroups are analyzed separately. The first subgroup, with branched inflorescences, narrowed rachillae, and concolorous lips, comprises a single specimen from Rio de Janeiro. It is recognized as a subspecies (subsp. gastoniana). The second subgroup, with branched inflorescences, non-narrowed rachillae, and bicolorous lips, comprises a subgroup of smaller sized specimens and a subgroup of larger sized specimens. There are too few smaller sized specimens to test for differences, but based on their small inflorescences with few (4-9) rachillae, they are recognized as a subspecies (subsp. kuhlmannii). The large sized specimens occur in two areas - inland areas in Cerrado of Brazil and adjacent countries, and the Atlantic Coastal Forest of Brazil. These two geographic subgroups differ from one another in 17 variables (petiole length, rachis length, number of pinnae, basal pinna length, basal pinna width, basal pinna angle, apical pinna length, apical pinna width, apical pinna angle, prophyll length, peduncular bract length, peduncle length, peduncle width, rachillae length, rachillae width, fruit length, fruit diameter) (t-test, P <0.05). They also differ in their triad arrangement. The Cerrado subgroup has mostly decussately arranged triads and the Atlantic Coastal Forest subgroup has mostly spirally arranged triads. Based on this and geographic separation, they are recognized as subspecies (subsp. pohliana, weddelliana). The third subgroup comprises specimens with mostly branched inflorescences, non-narrowed rachillae, and concolorous lips. One attribute serves to divide these specimens?the presence or absence of dense, wooly hairs on the rachillae. There are too few specimens for quantitative analysis, but using the rachillae hair attribute and geography, several distinct subgroups can be recognized. One subgroup from Espírito Santo, Minas Gerais, and Rio de Janeiro has short, narrow, densely hairy rachillae and is recognized as a subspecies (subsp. wittigiana). A second subgroup from Rio de Janeiro has long, thick, hairy rachillae, and is recognized as a subspecies (subsp. fiscellaria). A third subgroup from Rio de Janeiro has more, narrower pinnae (13-19 versus 3-7) and is recognized as a subspecies (subsp. trinervis). A fourth subgroup from Espírito Santo, Minas Gerais, Rio de Janeiro, and São Paulo has few, thick, non-hairy rachillae and is recognized as a subspecies (subsp. rodriguesii). A fifth subgroup from central Bahia has more numerous non-hairy rachillae and is recognized as a subspecies (subsp. rubescens). A sixth subgroup from near Una in Bahia has few, hairy rachillae and is recognized as a subspecies (subsp. unaensis). Finally, a seventh subgroup from southern Bahia with more, hairy rachilllae is recognized as a subspecies (subsp. linharensis). (Henderson, A.J. (2011) A revision of Geonoma. Phytotaxa 17: 1-271.)A

Description

  • Plants 2.9(1.0-6.0) m tall; stems 2.2(0.4-7.5) m tall, 1.3(0.6-2.9) cm in diameter, solitary or clustered, canelike; internodes 1.3(0.5-3.2) cm long, yellowish and smooth. Leaves 12(6-19) per stem, irregularly pinnate, not plicate, bases of blades running diagonally into the rachis; sheaths 15.9(6.0-50.0) cm long; petioles 33.0(4.5-89.5) cm long, drying green or yellowish; rachis 38.7(14.0-78.0) cm long, 3.8(1.6-10.1) mm in diameter; veins raised and rectangular in cross-section adaxially; pinnae 8(2-42) per side of rachis; basal pinna 33.6(9.3-70.0) cm long, 3.6(0.2-23.0) cm wide, forming an angle of 49(8-93)° with the rachis; apical pinna 23.9(7.5-46.0) cm long, 9.4(0.3-24.0) cm wide, forming an angle of 25(3-46)° with the rachis. Inflorescences unbranched or branched 1-2 orders; prophylls and peduncular bracts not ribbed with elongate, unbranched fibers, flattened, deciduous or persistent; prophylls 14.0(4.7-25.3) cm long, not short and asymmetrically apiculate, the surfaces ridged and densely tomentose with widely to closely spaced ridges, unequally wide, often dividing from and rejoining other ridges, the prophyll margins with irregular, spine-like projections, the prophylls usually splitting irregularly between the ridges; peduncular bracts 11.8(4.0-22.0) cm long, well-developed, inserted 2.3(0.2-12.5) cm above the prophyll; peduncles 15.9(5.0-34.5) cm long, 4.4(1.5-11.8) mm in diameter; rachillae 9(1?32), 19.0(5.5-39.5) cm long, 3.0(0.5-7.1) mm in diameter, the surfaces without spiky, fibrous projections or ridges, drying brown or yellow-brown, without short, transverse ridges, filiform with extended narrowed sections between the flower pits, or not filiform and not narrowed between the flower pits; flower pits usually spirally arranged, sometimes decussately or tricussately, then the groups not closely spaced nor consistently arranged throughout the rachillae, 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 or drying darker brown than 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 nonfertilized pistillate flowers not projecting and persistent after anthesis; fruits 9.3(5.5?13.2) mm long, 7.2(4.7?9.9) 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, sculpted, usually also with a raised, meridional ridge, without pores. (Henderson, A.J. (2011) A revision of Geonoma. Phytotaxa 17: 1-271.)A