Rhipsalis agudoensis N.P. Taylor, 2003

Gonzaga, Diego Rafael, Moraes, Lucas, Neto, Luiz Menini & Peixoto, Ariane Luna, 2016, Rediscovery, considerations about type locality and conservation of Rhipsalis agudoensis (Cactaceae) from the Brazilian Atlantic Forest, Phytotaxa 278 (1), pp. 74-78 : 76-77

Rhipsalis agudoensis N.P. Taylor , Cactaceae Syst. Init. 16: 12. 2003 ( Fig. 2 )

Type:— BRAZIL. Rio Grande do Sul: Agudo, Cultivated in Bonn, June 2003, Horst & Uebelmann 821 (holotype K!, image of the holotype available at http://apps.kew.org/herbcat/getImage.do?imageBarcode=K000372524).

Description:— Epiphyte, pendent; stem-segments, green, oblong, ribs 3–4, 1.2–1.7 cm long, ramification apical of growth determinate, 1–2-branched, 14.5–16.0 × 2.2–2.5 cm, glabrous, crenate margin, areoles about 2 mm diameter, 2.1–4.9 cm apart, pubescent to glabrous. Floral buds develop on the surface of the branches, cream, glabrous. Flowers about 5 × 10–14 mm long, 1–6 per areole, white to cream, bright; pericarpel 3–4 × 3 mm, emersed, green, oval; perianth segments about 10, tinted of rose, the external 1–2 × 2 mm, triangular, cream, the internal 3–7 × 2–4 mm, white, oblong, oval to lanceolate; stamens 59–88, white, 2–5 mm long; style 4–5 × 1 mm long, stigma about 2 mm long, white, 4–8-lobed, lobe about 1.5 × 1.0 mm, papillose. Fruits globose, truncated, hairless, rose to white, about 4 × 5 mm, perianth-segments persistent; seeds brown to black, elliptical about 1.5 × 1.0 mm.

Proposed vernacular name: —Cacto ‒ triangular (= Triangle-shaped cactus)

Distribution and habitat: — Brazil, Rio de Janeiro, Parque Nacional do Itatiaia, municipality of Itatiaia ( Fig. 1 ), as epiphyte in dense ombrophilous forest, at 800 m a.s.l., and district of Penedo (municipality of Itatiaia), distant about 9 km in a straight line from the first record. The specimens of this second record inhabit trees in an urbanized region, leading to a greater risk of habitat loss by predatory collection, replacement of trees and real estate expansion. There is another unconfirmed record, in the municipality of Três Rios, also in the Rio de Janeiro state, for an individual that did not show up fertile for one year already, with vegetative characteristics similar to Rhipsalis agudoensis (N.P. Taylor, pers. comm.)

Phenology: —Flowering time April ‒ May, fruiting time August.

Conservation status:— Larocca & Taylor (2013) treated Rhipsalis agudoensis as “Data Deficient” (DD; see IUCN 2016), due to the existence of only the type-specimen. The study carried out by Goettsch et al. (2015), that presented the assessments of all world cacti, also considered the species as “Data deficient” (DD). However, the collection of R. agudoensis ( Fig. 1 ) in the Parque Nacional do Itatiaia and Penedo district, both in the Itatiaia municipality (Rio de Janeiro state), allow us to define the conservation status. On the basis of the IUCN criteria and categories ( IUCN 2012), R. agudoensis is here assested as “Endangered” (EN) [criterion B2ab(ii,iii,iv,v)], the AOO of 8 km ² ( Moraes 2016). The species is threatened by the recurrent occurrence of human induced fires inside the Parque Nacional do Itatiaia ( Aximoff 2011), where intense tourism also pose a threat ( Barros 2003). The expressive industrial activities in the Itatiaia municipality also represent a threat, since it is responsible for the degradation of the area’s natural vegetation ( Castro 2001). Therefore, the species is subjected to continuing decline of its AOO, habitat quality, number of locations and number of mature individuals, justifying the subcriteria used in the assessment.

Material examined:— BRAZIL. Rio de Janeiro: Itatiaia, Parque Nacional do Itatiaia , 21 October 2014, Gonzaga D.R. et al. 358 (RB!) ; 20 March 2015, Gonzaga D.R. et al. 523 (RB!); Itatiaia, Penedo , 14 May 2016, Gonzaga D.R. et al. 682 (RB!) .

Figures

FIGURE 1. Distribution map of Rhipsalis agudoensis.

FIGURE 2. Rhipsalis agudoensis. A) Stem with floral bud and flowers; B) Flowers in details (photos by D.R. Gonzaga).