Moutabea floribunda Huber ex Silveira & Secco, 2015

Silveira, João Barros Da & Secco, Ricardo De S., 2015, A new species of Moutabea (Polygalaceae) for the Brazilian Amazon, Guyana and Peru, Phytotaxa 202 (4), pp. 259-265 : 259-263

Moutabea floribunda Huber ex Silveira & Secco , sp. nov. ( Figs. 1 & 2 ).

Species closely related to Moutabea angustifolia Huber but differs in having leaves smooth, with adaxially lustrous surface, raceme with rachis trimerous or tetramerous, seeds pubescent, and unnoticeable raphe.

TYPE:— BRAZIL. Amapá, 4 Nov. 1895, fl., J. Huber s.n. (holotype: MG 1200!).

Woody liana, scandent bush or small tree, 10–20 m tall, 11–20 cm diam. Twisted stem, rhytidome rough; branches cylindrical and glabrous, with aculea 2–3.5 mm long, puberulous, ovate to triangular, curved, base swollen. Leaf 12.5–26.5 × 5–9.5 cm, coriaceous, glabrous, obovate, oblong to oblanceolate, straight-ellyptical rare, apex acute to acuminate, base cuneate, round, margins entire, slightly revolute, surface smooth, adaxially lustrous, midvein usually plain, slightly prominent rare, secondary veins slightly indented on both sides, immerse rarely, small netted veins absent; petiole 0.8–1.8 cm long, glabrous, cross-section flat, blackened, articulated at the base, between two annular glands, ca. 1 mm diam. Raceme with rachis trimerous or tetramerous, monads rare, 1.5–2.5 cm long., glabrous to puberulous; bracts 3 at the base of the pedicel, 2.5–3 mm long, caducous, persistent rare, oval to lanceolate, ciliate, puberulous at the back, with two crateriform glands at the base; bracteoles 1.2–2.8 mm long, arranged in rosettes, persistent at the base of the pedicel, oval to oblanceolate, ciliate, puberulous at the back; flower 1.3–1.6 cm long, pedicel 0.5–1 mm long, calyx lobed, lobes 4–6 mm × 2–3 mm, lanceolate, oval to oblong, externally puberulent to glabrous, internally pubescent to velvety; corolla lobed, lobes 5.2–8 mm × 1.8–2.2 mm, oblanceolate, obovate to oblong, glabrous, stamens 8, in one single filament (staminal sheath) adnate to corolla, free part cucullate (staminal hood), densely pubescent at the back, margined by two groups of four anthers, back of the hood totally free, with opposite petal and staminal tube concrescent below the base of the hood (only in relation to the petal opposed to the hood); ovary 1–1.5 mm long, 1.2–2 mm diam, tetralobed (lobes not clearly defined); stylus 9–11 mm long, stigma capitate. Fruit globose and sub-globose, brown when immature (dehydrated material), surface smooth; seeds 1.7–1.9 cm long, velvety, raphe unnoticeable.

Additional specimens examined (paratypes): — BRAZIL. Acre: Ro Juruá, Juruá Miry , September 1901, fl., Ule 5842 ( MG 5746 ) ; Amazonas: Coari, Projeto Radam , ponto 17. SB. 20 VD, 20 September 1976, fl., T. R. Bahia 109 ( MG 55128 ) ; Amazonas: estrada Manaus-Porto Velho ( BR 319 ), Km 270-275, 20 September 1979, fr., A. S. Silva et al. 1362 ( MG 85715 ) ; Amazonas: Rio Urubu, between Cachoeiras Lindoia and Iracema, nearer to Iracema , 3 June 1968, fl., G. T. Prance et al. 4948 ( MG 38066 ) ; Amazonas: Manaus, estrad. Manaus-Itacoatiara , fl., 7 June 1968, G. T. Prance 5053 ( MG 41183 ) ; Amazonas: Reserva Florestal Duck, Manaus-Itacoatiara , Km 26, próx. à casa da torre, ao lado., 12 September 1995, fr., M. A. D. de Souza 94 ( MG 161117 ) ; Amazonas: Humaitá, Road Humaitá to Labrea , Km 42, 23 November 1966, fr., G. T. Prance et al. 3210 ( INPA 18787 ) ; Amazonas: Mun. Pres. Figueiredo, Estr. da UHE de Balbina , próx. ao igarapé do Barreto , 31 March 1986, fr., C. A. Ferreira et al. 7040 ( INPA 138674 ) ; Amazonas: Careiro-Castanho, Reserva de Desenvolvimento Sustentável Igapó-Açú , 18 September 2010, bt., E. M. B. Prata et al. 640 ( INPA 238947 ) ; Amazonas: Rio Aripuanã, Nova Prainha , 18 July 1976, st., J. Ramos et al. s. n. ( INPA 62181 ) ; Amazonas: Tapauá, Floresta Estadual Tapauá , 10 September 2010, bt., E. M. B. Prata et al. 454 ( INPA 238768 ) ; Amazonas: Manaus, mata entre Flores e os fundos da Colônia João Alfredo , 23 Jun 1940, fl., A. Ducke s. n. ( IAN 43445 ) ; Amazonas: Rio Negro, Arpão , Airão , 14 Jun 1948, fl. e fr., R. L. Froes 23254 ( IAN 36508 ) ; Amazonas: Rio Negro, Curucuhy , 17 Abr 1947, fr., R. L. Fróes 22158 ( IAN 28717 ) ; Amazonas: Manaus, Rio Tarumã , 8 Ago 1949, fr., R. L. Froes 24939 ( IAN 50771 ) ; Amazonas: Tefé, rio Solimões , 18 Out 1982, fr., I. L. Amaral et al. 128 ( UB 106509 ) ; Amazonas: Pres. Figueiredo, Rio Pitinga a 2 hrs. acima da confluência com rio Uatumã (a montante da UHE de Balbina), 21 March 1986, fr., C. A. Cid Ferreira et al. 6935 ( MO 04891250 ) ; Amapá: Mazagão, Rio Vila Nova , 13 July 1951, fr., R. L. Froes & G. A. Black 27458 ( IAN 64466 ) ; Mato Grosso: mun. Apiacás, rio Juruena , November 2007, fr., M. Sobral et al. 11266 ( BHCB 114883 ) ; Pará: Rio Jarí, margem direita entre Monte Dourado e S. Melitão , 20 March 1968, fr., E. Oliveira 4204 ( IAN 124440 ) ; Rondônia: Porto Velho, LT-Jirau - Santo Antônio , 22 October 2010, fr., G. Pereira-Silva et al. 15711 ( INPA 244969 ) ; Rondônia: Porto velho, sub-base do aeroporto, 17 Set 1975, fl., C. D. Mota & L. Coêlho 195 ( INPA 52697 ) ; Rondônia: Sub-base proj. RADAM, próximo do Aeroporto , 16 September 1975, fl., M. R. Cordeiro 800 ( IAN 150464 , MG 50904 ) ; Rondônia: Porto Velho, área de supressão do ramal Arrependido , à esquerda, 31 August 2011, fl. e fr., A. A. Santos et al. 3499 ( IAN 190237 ) ; Rondônia: Jaciparana , a margem da BR-364, próximo ao fragmento florestal de n. 10 da linha de transmissão, 22 October 2011, bt., B. M. Gomes 532 ( RB 577300 ) ; Rondônia: Porto Velho , 8 Set 1923, bt., J. G. Kuhlmann 399 ( RB 35817 ) ;

GUIANA. San Gabriel, 10 October 1929, est., N. Y. Sandwith s.n. ( RB 6746).

PERU. Madre de Dios, Shoreline of Laguna Cocacocha, 5.2 Km. down Main Trail. Explorer’s Inn, near the confluence of Rio Tambopata and Rio La Torre , 39 Km. SW. of Puerto Moldonado, 23 January 1989, fr, S. F. Smith et al. 1517 ( F 2033923 ) ;

Distribution and habitat:—Northeast of Peru, north of the Guyana, and Brazilian Amazon, in the states of Amapá, Pará, Mato Grosso, Rondônia, Acre, and more often Amazonas ( Fig. 3 ). Collected in ombrophilous forest dense or open, terra firme forest, flat or sloping relief, and mainly in clay or sandy-clay soil.

Phenology:—The species showed records of flower and fructification practically all year, except in February and December; floration peaked in September.

Conservation status:— Moutabea floribunda is a non-endemical species of the Brazilian flora. Extent of occurrence is wide in Brazil (EOO = 2.349. 807 km ²), and it is found in the states of Amapá, Pará, Mato Grosso, Rondônia, Acre, and more often Amazonas. Because the genus is poorly known and the lianescent habits make it difficult to collect branches with flowers and fruit in the highest forest layers, the species probably shows a small area of occupation (AOO = 104 km ²) compared to its extent of occurrence, which reflects low collection efforts. Restricted to the Amazon domain, it is observed in large areas of preserved forests, some of which are Conservation units (SNUC), which provide the conditions for its maintenance in nature. Due the widespread and abundant distribution of this species, we assign it a category of least concern (LC), according to the criteria of IUCN (2001).

Commentary:—This species is similar to M. angustifolia Huber , because both show indented secondary veins and completely free staminal hood. However, M. floribunda can be easily differentiated by its leaves with smooth, adaxially lustrous surface, raceme with rachis trimerous or tetramerous, monads rare, and seeds pubescent with unnoticeable raphe. It can also be differentiated from other related species according to described in Table 1.

The raceme with rachis trimerous or tetramerous, as the material examined here, is a consistent feature. However, M. floribunda . also shows leaves with smooth lustrous surface ( Fig. 2 ), which is unusual for the dehydrated Moutabea material. Also, there is a differentiated fusion pattern between the staminal sheath and the concrescent opposite petal, only common to M. angustifolia , which differentiates from M. floribunda by other features ( Table 1).

Figures

FIGURE 1. Moutabea floribunda. A: Habit, inflorescent branch. B: Flower, side view. C: Longitudinal section of flower, pistil removed. D: Pistil. E: Petal lobe. F: Sepal lobe, inner face. G: Sepal lobe, outer face. H: Leaf axil, detail of glands, bracteoles, and bracts. I: Top of the staminal sheath, back of the hood completely free. J: Aculleus. L: Immature fruit. M: Seed. (A: J. Huber s.n. (MG). B–I: M. R. Cordeiro 800 (MG). J: E.M.B. Prata et al. 640 (INPA). L: M.A.D. Souza et al. 94 (MG). M: A.S. Silva et al. 1362 (MG). Illustration by João Barros da Silveira.

FIGURE 2. Paratype of Moutabea floribunda (A. Sergio et al. 1362) showing leaves with adaxially smooth lustrous surface.

FIGURE 3. Distribution of Moutabea floribunda in the northeast of Peru, north of Guyana, and Brazilian Amazon.