Rhipsalis ewaldiana Barthlott & N.P. Taylor (1995: 66)

Gonzaga, Diego Rafael, Moraes, Lucas, Vasconcelos, Lucas Veronezi Feitosa De & Reis, Ricardo Carneiro Da Cunha, 2018, Rediscovery of Rhipsalis ewaldiana Barthlott & N. P. Taylor (Cactaceae): notes of morphology and conservation of an endemic and threatened species from the Brazilian Atlantic Forest, Phytotaxa 344 (3), pp. 291-294 : 292-293

Rhipsalis ewaldiana Barthlott & N.P. Taylor (1995: 66) ( Fig. 2 ).

Type: origin unknown. Cultivated in Univ. Bonn , Germany, Anonymous collector 603 BN 8780 (ex Ewaldi 31 May 1987, ex BG Gent) (holotype B-10-0525907!, image of the holotype available at http://ww2.bgbm.org/Herbarium/jacq_image.cfm?Barcode=B100525 907&idThumb=433636) ; ibid., cult. 1994 (paratype K-000250285!, image available at http://apps.kew.org/herbcat/getImage.do?im ageBarcode=K000250285) .

Description:— Epiphyte, pendent; stem-segments, dimorphic, green, the primary axes up to 13–22 × 0.2–0.4 mm, of indeterminate growth, 5–6-angled; secondary stem-segments similar, 1.8–2.0 × 0.3–0.35 cm, 3-angled, determinate growth; areoles ca. 1 mm diameter pubescent. Floral buds develop on the surface of the secondary stems-segments, lateral, cream. Flowers about 7 × 15 mm long. at anthesis, 1 per areole, white to cream, bright; pericarpel 2 × 1,5 mm, emersed, green, oval, glabrous; perianth segments ca. 9, the external 1–4 × 2 mm, triangular, cream, tinted of rose, the internal 5–8 × 3–3.5 mm, white, oblong to lanceolate; stamens 35, white, 3–5 mm long.; style 6 × 1 mm long, white, stigma about 4 mm long, white, 3-lobed, lobe about 2 × 1 mm, papillose. Fruits globose, truncated, hairless, white, about 7–8 × 6.5 mm, perianth-segments persistent; seeds black, elliptical about 1.3 × 0.7 mm.

Etymology: —The specific epithet was chosen in honor of Ernst Ewald, an enthusiastic collector of epiphytic cacti, who recognized it as unusual among Rhipsalis species ( Barthlott & Taylor 1995).

Distribution and habitat: — Brazil, Rio de Janeiro, Parque Estadual da Serra da Tiririca, municipality of Niterói ( Fig. 1), growing in the Atlantic Forest ( Ignácio et al. 2015) as epiphyte in dense ombrophilous forest, at 128–412 m a.s.l., in a sunny location, and in the forest edge region, in environments with some type of anthropic disturbance.

Phenology: —Flowering time July ‒ August, fruiting time August.

Conservation status:— AOO is 8 km 2 with only one single location. During the late eighties, the area was intensely deforestated due to an urban alottment attempt of the area, which induced several complaints and the creation of the Park ( Barros 2008). The area still suffers with intense urban development, as well as pressures generated from uncontrolled tourism activities, invasive species presence and fires ( Barros 2008). It is suspected that the aforementioned threats have as consequence the continuing decline of the species AOO, habitat quality, location number and number of mature individuals. The species was cited for the Minas Gerais state (Zappi & Taylor 2017), but this information was based in two occurence records of cultivated material from the “Fundação Zoobotânica”, in the Belo Horizonte municipality. These occurence records did not have any data regarding the origin of the samples. The species was assessed as “Data deficient” (DD; see IUCN, 2016) in the study conducted by Goetsch et al. (2015) and by Zappi & Taylor (2017), but the present data allows the reassessment of the species extinction risk category and criteria. Therefore, the species should be considered “Critically endangered” (CR) under the criteria B2ab(ii, iii, iv, v).

Material examined:— BRAZIL. Cultivated in Fundação Zoobotânica, Belo Horizonte-MG, unknown origin, 11 September 1997, Lombardi J.A. 1957 ( BHCB!) ; Cultivated in Fundação Zoobotânica, Belo Horizonte-MG, 04 July 2007, Costa M.C.D. ( BHCB!) ; Cultivated in Cactário of Jardim Botânico, Rio de Janeiro-RJ, unknown origin, 2016, Gonzaga D.R. 995 & Reis R.C.C. ( RB!) ; Rio de Janeiro: Niterói, Parque Estadual da Serra da Tiririca , 28 June 2016, Vasconcelos L.V.F. et al. 52 ( RB!) .

Figures

FIGURE 2. Rhipsalis ewaldiana. a. Habit; b. Steam; c. Stem with floral buds; d. Steam with flower; e. Flower in details; f. Steam with fruits (photos by D.R. Gonzaga and L. Moraes).