Rhipsalis occidentalis Barthlott and Rauh in Kakt. and Sukk 38: 17 (1987)

R> occidentalis, copyright Dereck Butcher

R. occidentalis, copyright Luc Scherens
DISTRIBUTION   Peru (San Martin), Ecuador (Napo, Morona-Santiago, Zamora-Chichipe), Suriname: epiphyte in perhumid equatorial forest, to c. 950 m altitude. 

This taxon is probably closely related to R. micrantha, but in contrast is very difficult to maintain in cultivation, which also distinguishes it from the superficially similar Brazilian species, R. oblonga.

DISTRIBUTION. Brazil (S Bahia, Espirito Santo?, Rio de Janeiro, Sao Paulo): epiphytic and epilithic in perhumid Atlantic forest, near sea level to c.1300 m altitude.

This taxon has the thinnest stem-segments amongst the Brazilian species and is very closely related to R. crispata, but appears to be rare in cultivation, where it needs some shade and high humidity to succeed. As to type, R. crispimarginata Lofgren (1918) is a synonym of R. oblonga, as has been confirmed by field studies at the type locality they share, but in cultivation this name is commonly misapplied to R. crispata (Haworth) Pfeiffer.

R. oblonga is also very similar to R. goebeliana from Bolivia and to R. occidentalis from northern Peru, southern Ecuador and Suriname. They differ from R. oblonga in their stem-segments being consistently narrowly cuneate at base, the pericarpel of R. goebeliana being more elongate and the flowers of R. occidentalis generally smaller than those of the Brazilian species.

A red-fruited variant or ally of R. oblonga, from the Serra dos Orgaos (RJ), with somewhat smaller but thicker stem-segments, is of uncertain taxonomic position and merits further study. It is sometimes encountered in cultivation under the inadequately typified name, R. rhombea (Salm-Dyck) Pfeiffer.



See Calvente Thesis 2010
Now treated as a synonym of Rhipsalia cuneata See Ralf Bauer, EPIG 62: 26. 2008

Rhipsalis occidentalis
Desc from Hunt 2006.
Like R. micrantha but branch segments always flat, up to 6.5cm diam, green or darkish red; flowers ca 8x10mm

Rhipsalis occidentalis Barthlott & Rauh , Kakteen und andere Sukkulenten (38) 1. 1987 translated by Luc Scherens and Derek Butcher.

A new species with leaflike flattened shoots from Ecuador and Peru

In the variously shaped, large genus Rhipsalis, the species with flattened, leaf-like shoots were gathered together by K. Schumann (1899) in a proper subgenus Phyllorhipsalis. The skilled observer F. Buxbaum acknowledged in 1970 for the first time, that this is an artificial merging of two groups of species that are not related : to unite the species with a basitonic-mesotonic branching and those with often big flowers with angular pericarp (e;g. Rhipsalis regnellii Lindberg). Buxbaum revised the subgenus Phyllorhipsalis Schumann emend. Buxbaum and Phyllarthrorhipsalis Buxbaum became separated as a new subgenus. This subgenus contains exclusively the East Brazilian species with acrotonic branching, small white flowers, naked round pericarp (e.g; R. pachyptera Pfeiffer, R. rhombea (S-D) Pfeiffer, R. crispata (Haw.)Pfeiffer). This very characteristic and natural group is limited to East-Brazil in its geographical description (majority of the species in the area between Rio de Janeiro and São Paulo).
Consequently, it was very surprising that the authors, during a common journey in Ecuador and Peru in 1973, collected a Rhipsalis species that unambiguously belongs to the subgenus Phyllarthrorhipsalis which was only known from East-Brazil until then.
A precise analysis of the growth, flowers, pollen, fruit and seeds has revealed in the meantime that – despite the strong superficial habitual resemblance – the plant is not identical to the known Brazilian species and supposedly not even closely related (probably evolved parallel with the Rhipsalis micrantha relationship). In this way this new species shall be described hereafter as Rhipsalis occidentalis. The name “occidentalis” means “western” and refers to the isolated occurrence of the species within a group of species that is only known from eastern South-America.

Rhipsalis occidentalis B & R spec. nov


(latin text)

Description :

Habit : up to 1 m long, overhanging epiphytic plant.
Branching : strongly acrotonic, i.e. young shoots almost exclusively from the apex of the older shoots.
Shoots : up to 6 cm long and 12 cm long, in culture often only half as big. Leaf-like thin flattened. Margins distinctively notched. The puny areoles without spines or visible wool in the notches of the shoots. Epidermis strongly (intensively) darkgreen, slightly shiny; on new growth often with a brown overlay.
Flowers : single (only occasionally with two) in the areoles, whitish, 10 mm wide and 9 mm long.
Tepals translucent whitish, about 7, up to 4 mm long and 3 mm wide, in full anthesis somewhat bent backwards, the top bend somewhat hood-like
Stamens : about 50 per flower, whitish, 4-5 mm long, inserted in a circle . The innermost stamen somewhat shorter than the outermost ones. Between stamen and style some nectar tissue, but not forming a clear disk.
Style: whitish, some 6 mm long, with 5-6 erect, strong papilla-like lobes, whitish. Pollen: 50µm in diameter, 6-colpat, with very small spinulae and numerous tectal perforations. Pericarp : cylindrical, greenish white, naked.
Fruit : young fruit at first dirty-brown-red, when ripe a some 7,5 mm long and 6,5 mm wide dirty-white, juicy berry. Rich fructification; plant obviously self-fertile.
Seed: some 60 per berry, 1,3 mm long, 0,5 mm wide, pointed at the apical end. Testa brown-black, border of the elongated testacells superficially very well recognisable, but – as with most of the Rhipsalis – without any conspicuous sculpture. Structure of the seeds reminds of Rhipsalis micrantha.
Habitat : Rain forest of Northeast Peru: Rioja(Dept; San Martin); altitude 800 m( holotype R & B nr 35392) and near Sucua (East Ecuador); alt. 950 m (R & B nr 34950). Jens Madsen (Bot. Inst. Univ. Aarhus, Denmark), within the scope of the editing of his “Flora of Ecuador”, brought two gatherings from East-Ecuador to our notice (personal statement). We can expect with certainty that the species is substantially wider spread, probably from East-Ecuador along the Andes till deep in Peruvian territory. Myron Kimnach (Huntington Bot. Gard. California) brings two gatherings from Bolivia to our notice (cultivated under HBG 50473 and HBG 53082 : M.K. personal statement), that are very probably to be assigned to this species. With this, the total area reaches possibly from southern Ecuador along the Andes to the Bolivian area.

The relationship and systematic position of the new species is added next: in vegetative state young plants in culture are hardly distinguished from the Brazilian species R. rhombea (S-D)Pfeiffer and R. goebeliana Backeberg. In non-flowering conditions the difference with R. goebeliana is the dark green epidermis ( R. goebeliana always noticeably light green); with R. rhombea the adult plants are distinguished by the larger shoots and the stronger hanging growth. When flowering and bearing fruits, the new species is distinguished by several characteristics : R. rhombea and R. goebeliana are flowering during winter in our culture (mainly in January), Rhipsalis occidentalis flowers in early summer (May/June; occasionally some flowers in February). The flowers are somewhat smaller and inconspicuous as with the two Brazilian species, they are purely white (with the two other species in question always clearly with yellow overlay); furthermore the species is lacking the reddish nectar tissue, a characteristic of Rhipsalis rhombea. R. goebeliana and R. rhombea are self-sterile and hardly give fruits, R. occidentalis is obviously self-fertile and gives a lot of fruits. While the new species has big, dirty-white berries, the fruits are smaller than the two Brazilian species, greenish in R. goebeliana and dirty-carminered in R. rhombea.

Seed and fruit structure raise the suspicion that R. occidentalis is not closely related to the Brazilian Phyllarthrorhipsalis at all, but belongs to the Rhipsalis micrantha (HBK) DeCandolle group. Here it would link the extreme form of a leaf-like flattened rainforest-epiphyte in a morphological line from R. kirbergii Barthlott over Rhipsalis micrantha and Rhipsalis rauhiorum Barthlott. Apparently it concerns a parallel evolution with the Brazilian species; with that it becomes an additional example for the systematically confusing, numerous convergences within the Cactaceae.

The new species, like most Rhipsalideae, is easy to cultivate; especially when having a rich fructification it is a decorative enrichment for our collections.
We are much obliged to Myron Kimnach (Huntington Inst. Cal.) and Jens Madsen (Bot. Inst. Aarhus, Denmark) for the additional information and to Mr. Thomas Engel (Inst. Syst. Bot. FU. Berlin) for checking the Latin diagnosis.

Pic 1 : fruiting plant of Rhipsalis occidentalis
Pic 2 : Flowering shoot of R. occidentalis (culture material from plant shown in fig. 1 and 3)
Pic. 3 : R. occidentalis in habitat near Rioja, North-Peru (R & B nr 35392). Watch the spreading-hanging growth and the size of the segments of this adult plant.
Fig. 4 a : Flower of R. occidentalis
Fig 4 b : longtudinal section thru the flower of R. occidentalis;


Top left photo: copyright Derek Butcher, top right photo: copyright Luc Scherens.

Below: photos copyright Ken Friedman

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