Notes: This species was originally described from
a collection from Bolivia (Williams 2458). However, the whole
range of geographic distribution and morphological variation in
natural populations of this species was unknown at the time of
its publication. For many years nobody was able to re-locate populations
of R. cuneata growing next to the type locality in Bolivia,
leading to taxonomic confusion. In particular, it was unclear
whether specimens with more delicate and narrower stem segments
with margins presenting narrower projections collected in Bolivia,
Peru and Ecuador belonged to R. cuneata or not. Barthlott
and Rauh (1987) preferred to recognize new collections from Peru
and Ecuador of individuals that resembled R. cuneata
as a new species (R. occidentalis), while Barthlott and
Taylor (1995) named the thinner forms of R.cuneata
from Bolivia as R. goebeliana. More recently, however,
Bauer (2008) made new collections of specimens thought to represent
R. cuneata, and R. occidentalis in Ecuador,
Peru and Bolivia and cultivated those specimens under standardized
conditions. Bauer (2008) observed that these specimens were very
similar morphologically when cultivated under standardized conditions.
Even the stem segments of R. cuneata from the type collection
(larger and stouter, with margins with deeper projections) changed
in cultivation demonstrating that the variation in stem morphology
is likely phenotypic plasticity, resulting from varying environmental
conditions and suggesting that all taxa listed above should actually
be recognized as a single species. Only a narrow form of R.
cuneata, from the Bolivian Chaparre seemed to maintain its
morphological variation in cultivation, hence deserving to be
treated as a subspecies (R. cuneata subsp. australis).
Rhipsalis goebeliana was excluded from this context,
as it was originally described from cultivated material with unknown
provenance (see notes under this species).
4.1 RHIPSALIS CUNEATA subsp. CUNEATAEpiphyte in shaded
habitat, 1 m long, branching apical or sub-apical. Stem segments
flattened to triangular in longitudinal section, 0.5-1.5 mm diam,
dark green, delicate, fragile, dimorphic, midrib 2-3 mm diam,
cylindric; primary stem segments 13-14 cm long; wings 2-3, with
cylindric base, 0.4-0.7 cm wide; secondary stem segments 5.5-17
cm long, base attenuate, apex truncate,wings 2(-3), 1.2-2.5 cm
wide, margin serrate, plane, rare slightly undulate, with 2-5
mm projections. Areoles between margin projections, 1.7-3.8 cm
apart, first of segment 4-8(-10) distant from segment base; when
sterile 1 mm diam, with 2 acicular reddish scales; when fertile
1.5 mm diam, with 1-3 acicular scales, 1(-2) flowers/fruits. Flowers
ca. 1 mm diam; pericarpel 2-4 X 2-3 mm, cylindric, greenish, glabrous
or with sepaloid bract; with 1-3 sepaloid tepals, 0.3-1.5 mm long
and 6 petaloid tepals, 3-4.2X2-2.3 mm, wide elliptic, patent to
sub-erect, whitish, apex rounded, slightly cucullate, margin straight.
Style 3-4 mm long; stigma with 3-5 lobes, ca. 1 mm long, ligulate,
spreading. Ovules in 3 rows, funicle short (< 0.5 mm long).
Stamens ca. 40, 1.5-2.5 mm long, internal shorter, internal erect
and external facing inwards, white. Nectary ca. 0.4 mm long. Fruit
7-9 X 7-8 mm, globose, whitish, glabrous. Figure7: A, H.Notes;
Rhipsalis cuneata subsp. cuneata can be distinguished
from R. cuneata subsp. australis by the wider
stem segments and deep projections in the margin.Habitat and distribution:
Occurs in the eastern lower Andean slopes of Ecuador and Peru,
reaching marginal Amazonian formations on lower elevations (200-1500
m). In Bolivia occurs in the "Yungas" of La Paz, Cochabamba
and Santa Cruz. An old collection from Suriname was also analyzed.
Although we did not examine specimens from other countries, it
is possible that this species might also occur in Colombia and
other countries of northern South America.Figure B.
Rhipsalis cuneata Britton and Rose Cact 4: 246 (1923)
Desc from B&R 1923
- Plant - epiphytic on trees;
- Joints - oblong to spatulate, 8 to 12 cm. long, thin, obtuse, cuneate at base, strongly crenate, naked at the areoles or with a bristle or two;
- Flowers - so far as known solitary;
- Fruit - globose, 4 mm. in diameter, naked.
Notes from Bradleya 13
DISTRIBUTION. Bolivia (La Paz): epiphyte in rain-forest, at 900-1700 m altitude.
A living collection was recently obtained by Pierre Ibisch, Univ. of Bonn, where it is now in cultivation. This species has thicker stems than its Andean allies R. goebeliana and R. occidentalis and in this respect closely resembles the Brazilian R. crispata.
Flower is potentially that of R. cuneata. (Photo copyright KAF 12-07)