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
45b.
Geonoma orbignyana
subsp.
hoffmanniana
(Wendland ex Spruce) Henderson
,
comb. & stat. nov.
Basionym:
Geonoma hoffmanniana
Wendland ex
Spruce (1871: 106)
. Type:
COSTA RICA
.
Heredia
: Volcán de Barba, no date,
H. Wendland s.n.
(
holotype
K!).
Geonoma molinae
Glassman (1964: 7)
. Type:
NICARAGUA
.
Matagalpa
: Santa María de Ostuma, between
Matagalpa
and
Jinotega
,
1300–1500 m
,
8 January 1963
,
L. Williams, A.
Molina
, & R. Williams 23507
(
holotype
F!).
Inflorescences
peduncular bracts 20.6(10.7–27.5) cm long; peduncles 32.4(20.9–56.0) cm long.
Distribution and habitat:—
From 8°52’–
13°02’N
and 82°33’–
86°20’W
in
Nicaragua
,
Costa Rica
, and
Panama
at 2008(1400–3000) m elevation in montane rainforest (
Fig. 30
).
This subspecies occurs in three separate areas;
Nicaragua
, the central part of
Costa Rica
, and eastern
Costa Rica
/western
Panama
.
There are six specimens from
Nicaragua
and these are small in size. There are no differences in any quantitative variable between these specimens and those of central
Costa Rica
, although they do occur at lower mean elevations (
1475 m
versus
2030 m
).
In central
Costa Rica
specimens occur on three separate Cordilleras; Pacific slope on Tilarán (Monteverde), Atlantic slope on Central (Barva); and Pacific and Atlantic slope on Central. Specimens from Tilarán (Monteverde) have unbranched inflorescences, as does one specimen from Central. Specimens from Barva and the Pacific and Atlantic slopes of Central are small in size and similar to those from
Nicaragua
.
In eastern
Costa Rica
and western
Panama
, on the Talamanca, some specimens are also small
(Davidse 26197, Fletes 1, Gamboa 708
) but the others are the largest of any area, and occur at higher elevations. These specimens occur sympatrically with large specimens of
G. undata
subsp.
edulis
.
Hammel
et al.
(2003)
considered that larger specimens of
subsp.
hoffmanniana
(as
G. hoffmanniana
) and sympatric
subsp.
edulis
(as
G. edulis
) were ‘virtually indistinguishable’.
There is geographical variation in this subspecies. Regression shows there are significant associations between elevation and one plant, three leaf, and one inflorescence variable. Squared multiple
R
for the regression of stem height on elevation is 0.32, rachis width 0.24, basal pinna length 0.43, apical pinna length 0.33, and peduncle width 0.17. Values of these variables increase with increasing elevation. Stems become taller, rachis wider, basal and apical pinnae longer and peduncles wider with increasing elevation.