Moutabea arianiae Jans.

Silveira, João Barros Da & Secco, Ricardo De S., 2018, Taxonomic studiesin Moutabea (Polygalaceae) in Brazil, Phytotaxa 365 (3), pp. 225-244 : 232

3. Moutabea arianiae Jans. -Jac. & Maas, Blumea 55(1): 86–87. 2010. ( Fig. 1 l–q )

Type:— FRENCH GUIANA.Basin of lower Oiapoque River, 18 April 1991, G. Cremers 12298 (holotype: U [U0255894 and U0255892 (fruits)]).

Liana or tree, to 30 m tall. Bark rough, epidermis densely velvety with smooth, brown trichomes. Juvenile branches pubescent. Leaf blades 14 ‒ 28 × 5 ‒ 8.5 cm, subcoriaceous, greenish adaxially, oblanceolate to obovate, glabrous to glabrescent adaxially (concentrations of trichomes sometimes on the midrib), pubescent abaxially (concentrated on the midrib and secondary veins), apex rounded to acute, base rounded to cuneate, margin thin, surface slightly wrinkled when glabrous, midrib plain, secondary veins sulcate adaxially, prominent abaxially; petioles 0.5 ‒ 1 cm long, pubescent. Racemes with rachis generally a monad, pubescent, 2 ‒ 3 cm long; flowers 1.3 ‒ 1.7 cm long, pedicels subsessile to sessile (<1 mm), sepal lobes 5 ‒ 7.5 mm long, 2.5 ‒ 4 mm wide, externally pubescent, internally glabrescent to pubescent, tips 6 ‒ 9 mm long, 1.2 ‒ 2 mm wide, staminal sheath with hood medium, glabrescent on the dorsum, group of 4 anthers ca. 1.5 mm long, ovary 1 ‒ 1.9 mm long, 1.5 ‒ 2 mm diam., tetralobed, style 7 ‒ 11 mm long, stigma capitate. Fruit orange when mature, pericarp ca. 1 mm thick, appearing ligneous in cross-section, surface smooth; seeds 2 ‒ 2.4 cm long, velutinous, raphe imperceptible.

Notes:—This species resembles M. victoriana J.B. Silveira & Secco and M. gentryi T. Wendt by its coriaceous leaves, with prominent secondary veins abaxially, thick pericarp and velutinous seeds.However, it is easily distinguished by the pubescence on its juvenile branches, petioles, abaxial leaf surface and inflorescences (vs. pubescence absent in M. gentryi and M. victoriana ).

For the genus, Moutabea arianiae is one of the easier species to recognize, primarily because of the indument on it its vegetative and reproductive parts. In addition, this species has more pronounced nodal and floral glands compared to other species of the genus.

Distribution and habitat: —Occurs in French Guiana ( Jansen-Jacobs & Maas 2010) and Brazil ( Fig. 2 ). In Brazil it occurs in the states of Amapá and Amazonas; the latter is a new record. Collected in slope forest, sandbank forest, and according to Jansen-Jacobs& Maas (2010) in primary forest, in clearings and on hills.

Conservation status: — Moutabea arianiae is not endemic to Brazil and its extent of occurrence (EOO= 77,208 Km 2) includes the states of Amapá and Amazonas. It has a small area of occupancy (AOO=12 Km 2), including preserved forest in one protected area that probably contributes to maintaining this species in nature. However, according to IUCN (2017) criteria, we recommend placing this species in the Data Deficient (DD) category due to the small number of collections.

Specimens examined: — BRAZIL. Amapá: Macapá, 6 January 1985 (fl.), S. Mori & J. Cardoso 17728 (HAMAB, MG, NY). Amazonas: Manaus,Reserva Florestal Ducke, 10 May 1995 (fr.), P. A. C. L. Assunção & C. F. da Silva 196 (INPA, RB); região do Rio Madeira, Rio Marimarí, October 1957 (fl.), R. L. Fróes 33713 (IAN, INPA).

Figures

FIGURE 1. Moutabea aculeata (Ruiz & Pav.) Poepp. & Endl. a. Branch with fruit. b. Flower. c. Adnation between staminal sheath and external petal (hood medium). d. Developed rachis, dehydrated and broken fruit with medium-thick pericarp. e.Glabrous seed with imperceptible raphe. (a from U. N. Maciel & C. S. Rosário 1626; b from S. A. M. Souza 966, c from D. C. Daly et al. 6969; d from R. P. Salomão1172; e from F. C. do Nascimento s.n.). Moutabea angustifolia Huber. f. Branch with inflorescence. g. Flower. h. Adnation between staminal sheath and external petal (hood concrescent). i. Immature fruit, subglobose and blackened. j. Broken fruit showing the thick pericarp. k. Seed glabrous and raphe into depression. (f–g from J. Jangoux & R. P. Bahia 61; h from B. S. Pena s.n.; i from U. N. Maciel & M. R. Santos 1903; j–k from B. V. Rabelo 1156). Moutabea arianae Jans.-Jac. & Maas. l. Branch with inflorescences. m. Abaxial pubscent surface of leaf. n. Flower with pubescent calyx. o. Adnation between staminal sheath and external petal (hood medium). p. Dehydrated and broken fruit showing the medium-thick pericarp. q.Velutinous seed. (l–o from S. Mori & J. Cardoso s.n.; p–q from P. A. C. L. Assunção & C. F. da Silva 196).

FIGURE 2. Geographical distribution of three species of Moutabea in Brazil: M. aculeata, M. angustifolia, and M. arianiae.