A revision of Geonoma (Arecaceae)
Author
Henderson, Andrew
text
Phytotaxa
2011
2011-02-18
17
1
271
journal article
24911
10.11646/phytotaxa.17.1
65962ba7-eec1-40e7-aed6-cef94e99ca39
1179-3163
3538362
47.
Geonoma pauciflora
Martius (1823: 12)
. Type:
BRAZIL
. State unknown: “in sylvis ad fluv. Amazonum”, no date,
C. Martius s.n.
(
holotype
M!).
Geonoma conduruensis
Lorenzi (2010: 226)
. Type:
BRAZIL
.
Bahia
: Itacaré, Fazenda São Miguel, km 43 rodovia Ilhéus-
Itacaré, 14˚23’S, 39˚03’W,
70 m
,
24 June 2008
,
H. Lorenzi, L. Noblick, & A. Guimarães 6498
(
holotype
HPL
n.v.
,
isotypes CEPEC
n.v.
, ESA
n.v.
, NY
n.v.
, RB
n.v.
, SP
n.v.
),
s
ynon. nov.
FIGURE 30
. Distribution maps of
Geonoma orbignyana
subsp.
hoffmanniana
,
G
.
paradoxa
,
G
.
pauciflora
,
and
G
.
peruviana
.
Plants
1.9(1.0–3.0) m tall; stems 2.3(1.5–3.0) m tall, 0.7(0.5–1.2) cm in diameter, solitary or clustered, canelike; internodes 2.0(0.9–2.9) cm long, yellowish and smooth.
Leaves
12(7–19) per stem, undivided or irregularly pinnate, not plicate, bases of blades running diagonally into the rachis; sheaths 8.4(3.7–15.5) cm long; petioles 12.8(4.5–27.0) cm long, drying green or yellowish; rachis 24.2(13.0–44.0) cm long, 2.5(1.2– 4.5) mm in diameter; veins not raised or slightly raised and triangular in cross-section adaxially; pinnae 2(1– 6) per side of rachis; basal pinna 17.5(10.5–26.0) cm long, 3.0(1.4–6.0) cm wide, forming an angle of 36(14– 66)° with the rachis; apical pinna 11.8(7.0–18.5) cm long, 8.3(5.0–18.0) cm wide, forming an angle of 30(17– 45)° with the rachis.
Inflorescences
unbranched or branched 1 order; prophylls and peduncular bracts not ribbed with elongate, unbranched fibers, flattened (if tubular, narrow, and elongate then not ribbed), deciduous or persistent; prophylls 13.5(7.0–19.0) cm long, not short and asymmetrically apiculate, the surfaces not ridged, without unequally wide ridges; peduncular bracts 12.4(5.4–18.5) cm long, well-developed, inserted 3.1(1.6–5.1) cm above the prophyll; peduncles 20.8(10.5–33.5) cm long, 2.7(1.2–5.0) mm in diameter; rachillae 3(1–6), 10.7(4.7–18.2) cm long, 2.9(1.6–4.3) 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 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 pistillate flowers not projecting and persistent after anthesis;
fruits
9.6(7.3–12.1) mm long, 7.4(5.6–8.5) 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; locular epidermis without pores.
Distribution and habitat:—
From 8°24’–
17°04’S
and 35°04’–
41°23’W
in the Atlantic Coastal Forest of
Brazil
from
Pernambuco
to
Bahia
, with an inland outlier in
Bahia
, at 291(20–770) m elevation in lowland rainforest (
Fig. 30
).
Taxonomic notes:—
The
type
locality is unknown. The label of the
type
specimen (“in sylvis ad fluv. Amazonum”) differs from the description (“in....Provinciarum Piauhiensis et Maraguaniensis”).
Geonoma pauciflora
is a member of a group of species from the Atlantic Coastal Forest and adjacent Cerrado of
Brazil
(the
G. schottiana
clade, also including
G. elegans
,
G. pohliana
, and
G. schottiana
). Although the group is well-supported, all constituent species are extremely variable internally.
Geonoma pauciflora
differs from
G. elegans
in its flattened prophylls and peduncular bracts which are not ribbed with elongate, unbranched fibers; from
G. pohliana
in its prophyll surfaces not ridged and without unequally wide ridges; and from
G. schottiana
in its undivided or irregularly pinnate leaves.
Subspecific variation:—
Three traits vary within this species (stem branching, leaf division, inflorescence branching). There is little geographic discontinuity, and the specimens are widely distributed in the northern part of the Atlantic Coastal Forest of
Brazil
. Leaving aside stem branching and leaf division, the remaining trait—inflorescence branching—does not divide the specimens into consistent groups. However,
Geonoma pauciflora
is variable in leaf division and inflorescence branching, and three morphotypes may be recognized.
The first morphotype has pinnate (rarely undivided) leaves and branched (rarely unbranched) inflorescences (
pinnate-branched
morphotype). This morphotype occurs in two separate areas;
Pernambuco
and
Alagoas
, and central and southern
Bahia
. The gap between these two areas is likely to be based on unsuitable habitat (W. Thomas, pers. comm.). However, there are too few specimens from
Pernambuco
and
Alagoas
to test for differences between the areas. Specimens of this morphotype from the most southerly part of the range in
Bahia
(e.g.,
Gentry 49920, Thomas 12020
) tend to have smaller leaves and inflorescences, and may be hybrids between
Geonoma pauciflora
and
G. elegans
(which see).
The second morphotype has undivided leaves and branched inflorescences, and occurs in central
Bahia
with an outlier further inland (
undivided-branched
morphotype). The
type
of
Geonoma conduruensis
is of this morphotype.
The third morphotype has undivided leaves and unbranched (rarely branched) inflorescences, and occurs in two localities in central
Bahia
(
undivided-unbranched
morphotype).