Geonoma undata Klotzsch, Linnaea 20: 452 (1847)

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Distribution

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

Discussion

  • Taxonomic notes: - Geonoma undata is a member of a group of high elevation, Andean species (the G. undata clade, also including G. lehmannii, G. orbignyana, G. talamancana, and G. trigona). These species have been treated differently by both Wessels Boer (1968) and Henderson et al. (1995). They are closely related and three of them - G. lehmannii, G. orbignyana, and G. undata are difficult to distinguish from one another, and extremely complex internally. In fact, G. undata is the second most variable species of Geonoma (Table 2). It differs from other species in this group by its prophyll surfaces which are ridged and densely tomentose with widely to closely spaced ridges, the ridges unequally wide, often dividing from and rejoining other ridges.

    Subspecific variation: - Five traits vary within this species (stem branching, stem type, leaf division, leaf plication, adaxial veins)(distal lip also varies but may be a result of hybridization, see under G. undata subsp. undata). Excluding stem branching and leaf division and the trait for which there are few data (stem type), the state distributions of the remaining two traits (leaf plication, adaxial veins) divide the specimens into three subgroups. One of these has non-raised adaxial veins and a discrete geographical range, and based on this is recognized as subspecies (subsp. stenothrysa). The second subgroup has plicate leaves and the third has nonplicate leaves. However, leaf plication is difficult to score in this species and does not divide the specimens into consistent subgroups. These specimens are therefore examined on a geographical basis. There are several geographically isolated subgroups, but usually too few specimens in each subgroup to test for differences. These subgroups are recognized as subspecies.
    There is an isolated subgroup in the Lesser Antilles (Dominica, Guadeloupe, and Martinique). There are only four specimens, but given their geographic isolation they are recognized as a subspecies (subsp. dussiana). There is an isolated subgroup in the Guayana Highland region of Venezuela and adjacent Brazil and Guyana. It differs from its nearest neighbors in Andean Venezuela in seven variables (stem height, number of pinnae, apical pinna width, apical pinna angle, prophyll length, rachilla length, rachilla width) (t-test, P <0.05). It is recognized as a subspecies (subsp. appuniana).There is an isolated subgroup from the Tumuc-Humac mountains in French Guiana and Suriname. There are only two specimens, but the flower pits tend to be decussately arranged and there are few pinnae (3-4) compared with other specimens and they occur at lower elevations (600-620 m). These are recognized as a subspecies (subsp. tumucensis). There is an isolated subgroup from Central America in Mexico, Guatemala, Honduras, Nicaragua, Costa Rica, and western Panama. It differs from the remaining specimens in seven variables (plant height, basal pinna width, apical pinna width, apical pinna angle, peduncle width, rachilla length, rachilla width) (t-test, P <0.05). It is recognized as a subspecies (subsp. edulis). There is an isolated subgroup from Cerro Tacarcuna in Panama. There are only two specimens but they have distinctive, distantly spaced flower pits and are recognized as a subspecies (subsp. tacarcunensis). There is an isolated subgroup from Andean Venezuela in Carabobo state. The two specimens have distinctive, pinnate leaves with narrow, linear pinnae and are recognized as a subspecies (subsp. venezuelana). There is a subgroup from eastern Andean slopes in Ecuador that have distinctive, narrow, linear pinnae and are reported to be rheophytes. These are recognized as a subspecies (subsp. pulcherrima ). There is a subgroup from Andean Ecuador which has distinctive, narrow rachillae and distantly spaced flower pits. It differs from other Ecuadorian specimens in 17 variables (plant height, stem height, internode length, leaf number, rachis length, rachis width, number of pinnae, basal pinna length, basal pinna width, basal pinna angle, apical pinna length, prophyll length, peduncular bract length, interbract distance, peduncle width, rachilla length, rachilla width)(t-test, P <0.05) and is recognized as a subspecies (subsp. skovii). The remaining specimens, from Andean regions of South America in Venezuela, Colombia, Ecuador, Peru, and Bolivia, are extremely variable and are not divisible into subspecies and are recognized as a single subspecies (subsp. undata). (Henderson, A.J. (2011) A revision of Geonoma. Phytotaxa 17: 1-271.)B

Description

  • Plants 5.4(0.9-17.0) m tall; stems 4.5(0.7-15.0) m tall, 2.0(0.9-5.0) cm in diameter, solitary or clustered, not cane-like or cane-like; internodes 1.3(0.5-5.7) cm long, yellowish and smooth. Leaves 10(4-17) per stem, undivided or irregularly pinnate, not plicate or plicate, bases of blades running diagonally into the rachis; sheaths 39.4(5.0-97.5) cm long; petioles 30.7(0.0-113.0) cm long, drying green or yellowish; rachis 101.1(17.0-265.0) cm long, 9.3(2.2-28.1) mm in diameter; veins raised and rectangular in cross-section adaxially or not raised or slightly raised and triangular in cross-section adaxially; pinnae 19(1-65) per side of rachis; basal pinna 43.3(14.0-83.0) cm long, 3.2(0.3-27.0) cm wide, forming an angle of 48(10-90)° with the rachis; apical pinna 32.7(8.0-66.0) cm long, 9.6(0.1-30.0) cm wide, forming an angle of 25(5-41)° with the rachis. Inflorescences branched 1?3 orders; 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(5.4-49.0) cm long, prophylls not short and asymmetrically apiculate, the surfaces ridged and densely tomentose with widely to closely spaced ridges, the ridges unequally wide, often dividing from and rejoining other ridges, the prophyll margins with irregular, spine-like projections (rarely these absent), the prophylls usually splitting irregularly between the ridges; peduncular bracts 18.7(7.0-39.0) cm long, well-developed, inserted 2.9(0.4-11.0) cm long; peduncles 18.4(4.7-50.0) cm long, 10.5(1.5-34.4) mm in diameter; rachillae 21(3-80), 19.7(5.0-54.0) cm long, 3.7(0.8-9.4) 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 usually spirally arranged, sometimes decussately or tricussately, then the groups not closely spaced nor consistently arranged throughout the rachillae, glabrous internally; proximal lips apiculate and lobed before anthesis, tearing in the center after 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 persistent after anthesis; staminodial tubes crenulate or shallowly lobed at the apex, those of non-fertilized pistillate flowers not projecting and persistent after anthesis; fruits 9.5(4.4-15.4) mm long, 6.9(3.8-12.0) mm in diameter, the bases with a prominent, asymmetric 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, sculpted, usually also with a raised, meridional ridge, without pores. (Henderson, A.J. (2011) A revision of Geonoma. Phytotaxa 17: 1-271.)B

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