Geonoma deversa subsp. deversa

Henderson, Andrew, 2011, A revision of Geonoma (Arecaceae), Phytotaxa 17, pp. 1-271 : 64-65

16a. Geonoma deversa subsp. deversa

Geonoma paniculigera Martius (1823: 11) . Lectotype (selected by Wessels Boer 1968): BRAZIL. “Pará et Rio Negro”, no date, C. Martius s.n. (M!).

Geonoma longipetiolata Ørsted (1858: 36) . Type: NICARAGUA. Río San Juan, no date, A. Orsted s.n. (holotype C, n.v.).

Geonoma microspatha Spruce (1871: 108) . Geonoma paniculigera var. microspatha (Spruce) Trail (1876: 327) . Type: BRAZIL. Amazonas: Rio Negro, Serra do Gama, São Gabriel, February 1853, R. Spruce 28 (holotype K!, isotype P!).

Geonoma microspatha var. pacimoensis Spruce (1871: 116) . Type: BRAZIL. Amazonas: Rio Casiquiare, no date, R. Spruce 41 (holotype K!, isotype P!).

Geonoma flaccida Wendland ex Spruce (1871: 108) . Type: COSTA RICA. Heredia: Río Sarapiquí, 1857, H. Wendland s.n. (holotype K!).

Geonoma paniculigera var. papyracea Trail (1876: 326) . Type: BRAZIL. Amazonas: Rio Javari, 8 December 1874, J. Trail 943/CXCIII (holotype K!).

Geonoma paniculigera var. cosmiophylla Trail (1876: 326) . Type: BRAZIL. Amazonas: Tabatinga, 30 November 1874, J. Trail 956/CLXXVII (holotype K!, isotype P!).

Geonoma paniculigera var. cosmiophylla subvar. gramineifolia Trail (1876: 327) . Type: BRAZIL. Amazonas: Tabatinga, 30 November 1874, J. Trail 958/CLXXVII (holotype K!, isotype P!).

Geonoma myriantha Dammer (1907: 120) . Type: BRAZIL. Acre: Rio Juruá, Juruá-mirim, September 1901, E. Ule 5882 (holotype B, destroyed, isotype MG!), s ynon. nov.

Geonoma leptostachys Burret (1930b: 1014) . Type: BRAZIL. Amazonas: Rio Negro, Camanaos, 26 September 1928, P. Luetzelburg 23072 (holotype B, destroyed, isotype M!).

Geonoma macropoda Burret (1930b: 1015) . Type: BRAZIL. Amazonas: Manaus, 26 August 1928, P. Luetzelburg 22089 (holotype B, destroyed, isotypes M!, R!).

Geonoma major Burret (1930b: 1016) . Type: BRAZIL. Amazonas: Rio Negro, Serra do Cucui, 25 September 1928, P. Luetzelburg 22273 (holotype B, destroyed, isotypes M!, R!).

Geonoma killipii Burret (1932a: 320) . Type: PERU. Junín: Puerto Bermudez, ca. 375 m, 14–17 July 1929, E. Killip & A. Smith 26594 (holotype B, destroyed, isotypes F!, NY!, US!).

Leaf rachis 38.9(17.2–80.0) cm long. Inflorescences peduncles 3.8(1.9–7.7) mm in diameter; rachillae 1.8(1.0–3.0) mm in diameter.

Distribution and habitat:— From 15°07’N– 17°00’S and 49°31’– 85°27’W in Central and South America at 246(5–1200) m elevation in lowland to montane rainforest ( Fig. 16 ).

There is a single specimen (Henderson 3024) from Herrera, Panama, isolated from others, which resembles specimens of subsp. peninsularis , particularly in its short peduncle and long rachillae, and it may represent a distinct subspecies.

Specimens from central Panama, from the Santa Rita Ridge to western San Blas have different shaped leaves, with shorter basal and apical pinnae with wider angles. Such specimens are also found just to the northeast of the Osa Peninsula, sympatric with subsp. peninsularis .

Several specimens, particularly from white sand regions of the Rio Negro in Venezuela and Brazil, but also less commonly from other areas, have regularly pinnate leaves with numerous pinnae with 1 main vein only. Some of these are reported to be rheophytes.

A few specimens, forming an isolated population in Pasco, Peru, are considerably smaller than others. They have wider basal pinna angles and sigmoid pinnae. The type of G. killipii is one of these specimens, and they are recognized as the killipii morphotype. Potential hybrids between this morphotype and G. brongniartii are discussed under that species.

There are several other areas where hybrids are suspected with other taxa. All these potential hybrids have been excluded from the above descriptions and analyses.

Specimens from the northeastern part of the range of the subspecies, in Suriname, French Guiana, and Brazil (Amapá, Pará), are intermediate in morphology between that of subsp. deversa and the sympatric G. leptospadix . Some of these specimens have leaves like those of subsp. deversa and triad arrangement approaching that of G. leptospadix ; some have leaves of G. leptospadix and triad arrangement of subsp. deversa . These specimens are hypothesized to be hybrids between the two taxa. There are a few other specimens from this region which also appear somewhat intermediate, but are determined as subsp. deversa . A hybrid zone may exist running from Suriname and French Guiana to Brazil (Amapá, Pará)(see Fig. 23 ).

There is considerable variation in the western Amazon region, and there may also be hybrid zones here, especially in Peru (Loreto) and Brazil (Acre). Specimens from near Iquitos (iquitos morphotype) differ from other specimens of subsp. deversa in 13 variables (plant height, stem diameter, petiole length, rachis length, rachis width, basal pinna length, interbract distance, peduncle length, peduncle width, rachilla length, rachilla width, number of rachillae, fruit diameter)(t -test, P <0.05). On the other hand, the same specimens differ from the sympatric subsp. quadriflora in only four variables (peduncle width, rachilla width, fruit length, fruit diameter) (t -test, P <0.05). These results indicate that the iquitos morphotype may represent hybrids between subsp. deversa and subsp. quadriflora (specimens of subsp. quadriflora may have tricussate pits at the apices of the rachillae, and one specimen of subsp. deversa (Croat 20340) contains two inflorescences, one with quadricussate pits and the other with tricussate pits).

Some specimens from the western Amazon region of Brazil (Acre, Amazonas) differ from the more typical subsp. deversa in their longer leaves with more pinnae, and shorter, thicker peduncles. In their leaves they resemble subsp. quadriflora and in their inflorescences they resemble G. occidentalis , and they occur in an area between the ranges of these two taxa. They may be hybrids between subsp. quadriflora and G. occidentalis , or between one of these taxa and subsp. deversa . The type specimen of G. myriantha appears to represent one of these possible hybrids.

Figures

FIGURE 16. Distribution maps of Geonoma deversa subsp. deversa, G. deversa subsp. belizensis, G. deversa subsp. peninsularis, and G. deversa subsp. quadriflora.

FIGURE 23. Distribution maps of Geonoma leptospadix and G. longipedunculata.