Neea contracta D.S.Costa & E.F.S.Rossetto, 2025

Costa, Daniel da S., Rossetto, Elson Felipe S. & Giacomin, Leandro L., 2025, Neea contracta (Nyctaginaceae), a New Species from Amazonia, Systematic Botany (Basel, Switzerland) 49 (4), pp. 743-748 : 743-747

Neea contracta D.S.Costa & E.F.S.Rossetto , sp. nov. TYPE: BRAZIL. Amazonas: Manaus, Reserva Florestal Ducke, Manaus-Itacoatiara, Km 26. Floresta de Vertente, 2 52 9 60.00”S, 59 58 9 0.00 99 W, 07 Nov 1996 (fl), M.R. Mesquita 14 (holotype: INPA!, isotypes: IAC, L, MO!, NY!, RB!, SP!)

Neea contracta can be distinguished from other Brazilian species of Neea by the following unique combination of characters: non-woody short peduncles (0.8–1.5 cm long), reduced rachis (3–6 mm long), inflorescence branched up to one time, and pistillate flowers with subcylindrical perianths.

Shrub or tree, 1.5–8 m tall. Bark smooth, grayish brown, lenticillate; inner bark and sapwood yellowish, oxidizing fast; branches cylindrical and dichotomously branching, grayish, glabrescent. Leaves opposite and subopposite, drying blackish; petiole 0.4–(0.8 6 0.3)–1.5 3 ca. 0.2 cm, glabrous; blades 5.8–(8 6 2)–13 3 2.5–(3 6 0.8)– 5.5 cm, elliptic or obovate, consistency chartaceous, surface smooth and glabrous; base symmetric, acute or attenuate; apex acuminate or cuspidate; margin entire. Midvein pinnate, abaxially and adaxially prominent or impressed; secondary veins brochidodromous, in 6–(7.5 6 1)–10 pairs, abaxially and adaxially impressed or prominent, at an angle of 93–95, regularly spaced; intersecondary veins, 1 cm apart from the secondary veins, approximately 1 per intercostal area; tertiary veins ramified. Inflorescences cymes, 1-branched (see Fig. 1B ), 1–(1.5 6 0.5)– 2.3 cm long, terminal or axillary, erect; peduncles 0.8–(1 6 0.2)–1.5 3 ca. 0.2 cm, non woody, erect, glabrous to sparsely puberulous with reddish trichomes; bracts at base of inflorescence 1–2 mm long, deltoid, glabrous to sparsely puberulous with reddish trichomes getting more dense in the ventral portion, commonly caducous; rachis 3–(5 6 1)– 6 mm long, glabrous to sparsely puberulous with reddish trichomes, primary branches bifurcating (dichasial), bearing 2–3 flowers in a terminal dichasium, reaching a maximum of 7 mm long on the basal portion and absent on the apical portion of the inflorescence, with the flowers growing on the distal portion of the primary axes and developing on the rachis near the apex of the inflorescence (see Fig. 1B ); bracteoles 1–3 per flower, often irregular, 1–(2 6 1)– 3 mm long, deltoid, glabrous. Staminate buds and flowers not observed. Pistillate flowers 4–(6 6 2)–9 3 1–(1.2 6 1)– 2 mm, subcylindrical, glabrous, with a constriction in the middle portion of perianth, perianth 5-lobed, the lobes deltoid, with ventral surface papillate, slightly erect at apex, ovary ellipsoid to ovoid; style 2.5–(3.3 6 0.7)– 4.1 mm long; stigma lacerate; staminodia 5–6. Infructescences erect, 1.3–(2.7 6 0.2)– 3 cm long, glabrous. Fruit an anthocarp, 1–(1.5 6 0.3)–2 3 0.6–(1 6 0.3)– 1.5 cm, ellipsoid, glabrous; apical cupule 0.2–(0.3 6 0)– 0.3 mm, 5-lobed.

Distribution and Habitat — Neea contracta is known from central Amazonian Brazil, in the municipalities of Manaus and Rio Preto da Eva (Amazonas State) ( Fig. 2 ). The species grows in terra firme forests (non-flooded) on sandy or clayish soils, at 63–95 m above sea level.

Etymology —The epithet refers to the reduced branches of the inflorescence, giving it a contracted aspect.

Notes —Based on morphological characters and the geographical distribution, Neea contracta is morphologically similar to N. parviflora and N. oppositifolia , both of which also have the inflorescence with a congested appearance.

Neea parviflora is also an Amazonian species ( Fig. 2 ) and, besides the inflorescence aspect, it shares several vegetative and reproductive characteristics with N. contracta (e.g. shape of the leaves, dimensions of the peduncle, insertion of the inflorescence, and length of the bracteoles) and we consider it to be the most morphologically similar species. However, N. contracta can be distinguished from N. parviflora by the indumentum of the leaves (glabrous vs. softly and densely puberulent with purple-red trichomes), length of the bracts (1–2 mm long vs. 2.5–7 mm long), disposition of flowers on the terminal inflorescence branches (flowers borne in a dichasium, on the distal portion of the primary branches and rachis vs. flowers in a packed sessile monochasium, with glomerule like aspect), pubescence of pistillate flowers (glabrous vs. softly pilose in basal region) and length of the anthocarps (1–2 cm long vs. 0.5 cm long).

Neea contracta can be easily distinguished from N. oppositifolia based on the peduncle indumentum (glabrous vs. pubescent), inflorescence disposition (erect vs. pendulous), length of the inflorescence branches (up to 7 mm long vs. 12–25 mm long), inflorescence ramification (1-branched vs. 2–manybranched), bracteole indumentum (glabrous vs. pubescent), and length of the apical cupule of the anthocarps (0.2–0.3 mm long vs. 1–2.5 mm long).

Previous studies have demonstrated the efficiency of NIRS at delimiting species of Neea ( Costa et al. 2023) . The correct prediction rate in our discriminant model (cross validations) for all species was 80%. In this discriminant model, no incorrect prediction was recorded for Neea contracta (100% correct predictions); for N. oppositifolia the percentage of correct predictions was 89% (two specimens were incorrectly predicted as N. parviflora ), while for N. parviflora the percentage of correct predictions was 67% (two specimens were incorrectly predicted as N. oppositifolia ) ( Fig. 3 ).

Additional Specimens Examined— Brazil. — AMAZONAS: Manaus , Reserva Florestal Adolfo Ducke, area proxima a torre, 2 53 9 0.00”S, 59 57 9 60.00 99 W, 06 May 1995 (fr), C. A. Sothers & E. C. Pereira 429 ( IAN!, INPA!, MBM, NY) ; Humaita , Br 319, Manaus-Porto Velho, a 15 km de Humaita 7 39 9 60.00”S, 62 59 9 60.00 99 W, 10 Apr 1985 (fl), C. A. C. Ferreira 5401 ( INPA!) ; Manaus , Reserva Florestal Adolfo Ducke, estrada de acesso, 2 53 9 0.00”S, 59 58 9 0.00 99 W, 08 Apr 1988 (fr), J. P. Santos & R. P. Lima 896 ( INPA!, R, US) ; Manaus , Reserva Florestal Adolfo Ducke, Igarape do Acara, 2 53 9 0.00”S, 59 57 9 60.00 99 W, 06 Jan 1977 (fr), M. F. Silva & D. Co^elho

2018 (INPA!); Rio Preto da Eva , AM-010, Estrada Manaus-Itacoatiara , km-118, ramal do Procopio ( DERAM), Igarape do Procopio, 2 45 9 0.00”S, 59 24 9 0.00 99 W, Apr 1976 (fr), O. P. Monteiro & J. Ramos 669 ( INPA!) ; Manaus , Reserva Florestal Adolfo Ducke, Floresta de vertente, 2 53 9 0.00”S, 59 57 9 60.00 99 W, 17 Jan 1997 (fr), P. A. C. L. Assunç ~ ao & E. C. Pereira 449 ( INPA, NY, R, SP) ; Manaus , Reserva Florestal Adolfo Ducke, Q. XVI, 2 53 9 0.00”S, 59 57 9 60.00 99 W, 07 May 1966 (fr), W. A. Rodrigues & D. Coelho 7808 ( FUEL!, INPA!) .

Figures

FIG. 1. Isotype of Neea contracta D.S.Costa & E.F.S.Rossetto (from M.R. Mesquita 14; RB [RB352746]). A. Flowering branch. B. Detail of pistillate inflorescence. C. Pistillate flower. D. Detail of pistillate flower. Image reproduced with permission from the RB Herbarium.

FIG. 2. Known distribution of Neea contracta D.S.Costa & E.F.S.Rossetto and two morphologically similar species, N. parviflora and N. oppositifolia.

FIG. 3. A. The confusion matrix generated by a linear discriminant analysis (LDA) classifier to classify species based on spectral variables. In the matrix layout, observed species’ names are positioned in rows, while predicted names are positioned in columns. Hence, entries along the diagonal indicate correct predictions, whereas those outside the diagonal signify prediction inaccuracies. B. Mean spectra for each species tested.