Amorimia andersonii R.F.Almeida, 2016

Almeida, Rafael Felipe De, Berg, Cássio Van Den & Amorim, André Márcio Araujo, 2016, Untangling the Amorimia rigida complex, a puzzling group of lianescent Malpighiaceae from Eastern Brazil, Phytotaxa 284 (1), pp. 1-23 : 4-8

1. Amorimia andersonii R.F.Almeida , sp.nov. ( Figs. 1 , 3 , 11–12 )

Type: — BRAZIL. Bahia: Mun. Itamaraju, Serra ao lado do Morro do Pescoço, entrando pela Fazenda Novo Horizonte e passando pela propriedade do Sr. Ailton, área rochosa no alto da serra, 16 February 2014, fl. fr., L.C. Marinho, A.M.A. Amorim, R. Goldenberg & L. Daneu 654 (Holotype: CEPEC!; isotypes: HUEFS!, P!, RB!) .

Differs from Amorimia rigida by its leaves lanceolate to elliptic to narrow-elliptic, 10–16 pairs of secondary veins, bracts and bracteoles reflexed to the peduncle; sepals revolute at anthesis; petals entirely velutine adaxially; anterio-lateral petals overlapping; filaments pubescent at apex; apex of styles uncinate; dorsal wing of samaras depressed ovate, lower angle of lateral wings narrower.

Woody vines to scandent shrubs; stem sparsely velutine to glabrous at age; stipules 0.4–0.6 mm long, triangular, epipetiolar, deciduous. Leaves subopposite, not reduced in inflorescences; petioles 6.5–8 mm long, sparsely sericeous-velutine to glabrous, eglandular at apex; leaf blades 5.15–11.5 × 1.6–4.3 cm, plane, not bullate, lanceolate to elliptic to narrow-elliptic, base cuneate to attenuate, margin revolute, apex acute, adaxially glabrous, abaxially sparsely velutine to glabrous, 1 pair of glands, 0.6–0.7 mm diam., near base or up to 0.8–0.9 mm of margins; midvein adaxially impress, abaxially prominent, 10–16 pairs of secondary veins, arching 60°–64°, subopposite to alternate, adaxially impress, abaxially prominent, reticulum adaxially impressed and inconspicuous, abaxially prominent and conspicuous. Thyrses (pseudoracemes), axillary; main axis 9.4–15.2 cm long, cylindrical, smooth, velutine; cincinni 20–40, 1-flowered, proximally spirally alternate, distally decussate; bracts 3.5–5 × 1–1.2 mm, lanceolate, conduplicate, subsessile, reflexed to peduncle, 1 pair of marginal glands near base, both sides minute velutine; peduncle 5–8 × 1–1.3 mm, velutine; bracteoles 1.5–2.5 × 1.0– 1.2 mm, elliptic, sessile, inserted 0.5–2 mm below the apex of peduncles, opposite to subopposite, reflexed to the peduncle, 1–2 glands near base, both sides velutine; pedicels 6–7.5 × 1.5–1.7 mm, velutine. Flowers 13–14 mm diam. at anthesis; floral buds 5–6 × 4–5 mm. Sepals 0.5–1 × 0.5 mm, narrowly oblong, not appressed to the androecium, apex acute, obtuse to rounded, revolute at anthesis, both sides sericeous-velutine; glands yellow turning ocher at age, 1–1.2 × 0.3–0.5 mm. Petals bright yellow, not turning darker at age, margin sinuate, anterior-lateral petals overlapping; lateral petals patent at anthesis, anterior-lateral petals overlapping at anthesis, limb 2.4–3.4 × 1–1.2 mm, wide elliptic, base truncate, adaxially distally velutine, abaxially sericeous-velutine; claws 0.5– 0.8 × 0.2 mm, adaxially velutine, abaxially sericeous-velutine; posterior petal erect at anthesis, limb 1.4–1.5 × 1.2–1.3 mm, wide elliptic, base cuneate, adaxially velutine, abaxially sericeous-velutine; claw 1–1.2 × 0.3–0.4 mm, adaxially velutine, abaxially sericeous-velutine. Stamens 10, those opposite petals shorter than those opposite sepals, except for the one opposite to the anterior sepal which is shorter than others; filaments 1–1.6 × 0.4–0.6 mm, connate 0.4–0.5 mm long at base, sericeous at apex; anthers heteromorphic, recurved with a glandular connective, 0.8–1 × 0.4–0.6 mm, reflexed in anthesis, base, connective and apex pubescent. Ovary 1–1.1 × 0.9–1 mm, each carpel with primordial lateral and dorsal wings, sericeous-velutine; styles 3, cylindrical at base, flattened and curved at apex, parallel at base, divergent at middle, apex truncate with uncinate angle, sericeous-velutine at base, anterior style 1.2–1.4 mm long, posterior styles 1.4–1.6 mm long; stigma lateral, discoid. Samaras (immature) green in vivo; dorsal wing ca. 6.3 × 1.5 mm, depressed ovate, margin entire, velutine on both sides; lateral wings 8–17.2 × 4–17.9 mm, flabelliform, margin entire to sinuate, upper angle 58°, lower angle 63° from the nut, both sides velutine to glabrous; nut ellipsoid, velutine; areole ca. 1 × 0.5 mm. Seeds not seen.

Specimens analyzed: — BRAZIL. Bahia: Itamaraju, Morro do Pescoço , ca. 15 km da entrada da cidade, 11 February 2007, fl., Amorim 6856 (CEPEC) ; loc. cit., 16 February 2014, fl., Marinho 676 (CEPEC) .

Distribution, habitat and phenology: — Amorimia andersonii is only known from Semi-deciduous forests associated to rocky outcrops in southern state of Bahia ( Fig. 12 ), flowering in February.

Conservation status: — Amorimia andersonii is known by only three collections from Semi-deciduous Forests, associated to rocky outcrops within the Atlantic Forest of southern Bahia. Thus, this species should be regarded as Critically Endangered (categories B1a and B1b), due to its range of distribution being about 4.678 km ² and continually declining habitat quality.

Etymology: —The epithet honors the North American botanist Dr. William Russell Anderson (1942–2013†), late colleague, and longtime contributor in the studies of Neotropical Malpighiaceae .

Taxonomic notes: — Amorimia andersonii resembles A. rigida on sepal and anther indumenta, but differs on indumentum type, leaf shape, size of peduncles at anthesis, position of bracts and bracteoles, position of sepals, color of sepal glands, color of petals, petal indumenta, thickness of the posterior petal claw, position o anterior-lateral petals, filaments indumenta, shape of apex of styles, and shape of dorsal wings of samaras. A list of informative characters to differentiate them is presented on Table 1.

Figures

FIGURE 1. Amorimia andersonii R.F.Almeida:A. stem leaf; B. abaxial view of a leaf base showing a pair of glands; C. flowering branch; D. inflorescence showing floral buds and flowers; E. detail of sepal glands; F. flower in frontal view; G. detail of a style; H. Seasonally Dry Forest associated to rocky outcrops in Southern Bahia state (photographs C, H by A.M.A. Amorim; A–B, D–F, G by F. Michelangeli).

FIGURE 3. Amorimia andersonii R.F.Almeida (based on L.C. Marinho 654): A. abaxial side of a leaf showing vein pattern; B. posterior petal in adaxial view; C. posterior-lateral petal in adaxial view; D. anterior-lateral petal in abaxial view; E. androecium, the first stamen on the left is opposite the anterior sepal; F. stamen showing hairy anther; G. gynoecium showing the anterior style at center. Amorimia candidae R.F.Almeida (based on R.F. Almeida 594): H. abaxial side of a leaf showing vein pattern; I. posterior petal in adaxial view; J. posterior-lateral petal in adaxial view; K. anterior-lateral petal in abaxial view; L. androecium, the first stamen on the right opposite the anterior sepal; M. stamen showing hairy anther; N. gynoecium showing anterior style at center (drawings by Klei Sousa).

FIGURE 11. Illustration plate comparing flowers and fruits from species of the Amorimia rigida complex: Amorimia rigida, A. flower in frontal view, G. samara in dorsal view; Amorimia candidae, B. flower in frontal view, H. samara in dorsal view; Amorimia coriacea, C. flower in frontal view, I. samara in dorsal view; Amorimia pellegrinii, D. flower in frontal view, J. samara in dorsal view; Amorimia andersonii, E. flower in frontal view, K. mature samara unknown; Amorimia velutina, F. flower in frontal view, L. samara in dorsal view (photographs A, B, D, G, H, J—R.F. Almeida, C—M.O.O. Pellegrini, E—F. Michelangeli, I—C.N. Fraga).

FIGURE 12. Distribution map of species from the Amorimia rigida complex in eastern Brazil: white circle—A. andersonii, black circle— A. candidae, white square—A. coriacea, gray triangle—A. pellegrinii, black triangle—A. rigida, dark star—A. velutina. White area— Caatinga domain, light gray area—Atlantic Forest domain, dark gray area—Cerrado domain, dark area—Amazon Forest domain.