Rhipsalis triangularis Werderm.

Braga, João Marcelo Alvarenga & Freitas, Maria de Fátima, 2010, Neotypification of Rhipsalis triangularis Werderm. (Cactaceae), a critically endangered species from southeastern Brazil, Adansonia (3) 32 (2), pp. 235-238 : 237-238

Rhipsalis triangularis Werderm.

( Fig. 1 )

Feddes Repertorium Specierum Novarum Regni Vegetabilis 42: 3 (1937). TYPE. — Brazil. “ Estado do Rio de Janeiro, Município do Rio de Janeiro, Maciço da Pedra Branca , Parque Municipal Natural da Prainha, Pedra dos Cabritos, Mirante Boa Vista, 340 ms.m.”, 6. VI.1996, J. M. A. Braga & M.G. Bovini 3357 (neo-, RB! [here designated]; isoneo-, RUSU!, R!) . OTHER MATERIAL EXAMINED. — Brazil. RJ, Rio de Janeiro, Pedra Branca Massif, between the Prainha Municipal Natural Park and the Pedra Branca State Park , 25. V.2003, J.M.A. Braga 7210 ( RB). — Prainha Municipal Natural Park, 17.IV.2003 , A. M. Calvente & M. Bocayuva 37 ( RUSU). — Eod. loc., 15. V.2004, A. M. Calvente & L. Versieux 87 ( RUSU). — Cruzeiro do Sul , 6. VI.2003, A.M. Calvente et al. 42 ( RUSU). — Eod. loc., 10.X.2004 , A. M. Calvente & L. Versieux 112 ( RUSU). — Eod. loc., 12.XII.2003 , L. J. T. Cardoso & C.A. Zaldini 51 ( RB) .

REMARKS

Rhipsalis triangularis was documented for the first time in its natural habitat in 1996, during an expedition to Pedra Branca Massif, in southeastern Brazil. Searches for the species were intensified over the following years in the region, and this has resulted in new collections in the neighbouring area of the Prainha Municipal Natural Park and Pedra Branca State Park, both located on the Rio de Janeiro State coast in Brazil ( Fig. 2 ).

These recent discoveries allowed Calvente & Andreata (2007) to describe the Rhipsalis triangularis morphology and natural habitat in detail, but these authors did not address the question of formal typification of the name.

Rhipsalis triangularis is a heliophyte species which forms dense islands of vegetation on the rocky outcrops ( Fig. 2 ) or appears rarely as epiphytes on sunlit open canopy trees. Th is species probably reproduces also vegetatively and the basal stem segments sometimes have the margins lacerated ( Calvente & Andreata 2007). The flowers are white, abundant and visited by many different species of bees ( Fig. 3 ). The flowers and fruits are synchronic and collected along April, May, June, October and November.

According to the IUCN (2001) criteria, Rhipsalis triangularis is categorized as critically endangered – CR (B2b), with a known occupation area of less than 10 km ². Th is species is also listed in the CITES checklist ( Hunt 1992), although it is not included in the recent offi cial lists of Brazilian species threatened with extinction (i.e. Costa 2000; IBAMA 2008).

Figures

FIG. 1. — Rhipsalis triangularis Werderm.: A, habit; B, Stem segment with crenate margins; C, areole with scales and hairs; D, transversal sections of the stem segments 3, 4 and 5-winged; E, flower; F, longitudinal section of the flower; G, fruit. J.M.A. Braga & M.G. Bovini 3357. Illustration by Paulo Ormindo. Scale bars: A, not to scale; B, D, 3 cm; C, 2 mm; E-G, 1 cm.

FIG. 2.– Rhipsalis triangularis Werderm.in its natural habitat (Pedra Branca Massif, Rio de Janeiro State, Brazil).

FIG. 3. – Flowers and buds of Rhipsalis triangularis Werderm.