Ameroglossum alatum E.M.Almeida, A.M.Wanderley & L.P.Felix, 2021

Almeida, Erton M., Christenhusz, Maarten J. M., Wanderley, Artur Maia, Cordeiro, Joel Maciel P., Melo, José Iranildo Miranda De, Batista, Fabiane Rabelo Da Costa & Felix, Leonardo P., 2021, An overview of the Brazilian inselberg genus Ameroglossum (Linderniaceae, Lamiales), with the description of seven new species, European Journal of Taxonomy 746, pp. 1-25 : 6-7

Ameroglossum alatum E.M.Almeida, A.M.Wanderley & L.P.Felix sp. nov.

urn:lsid:ipni.org:names:77216325-1

Figs 2A , 3a–e

Diagnosis

A species morphologically similar to A. manoelfelixii because it has glabrous to glabrescent, lustrous vegetative parts and inflorescences. However, A. alatum sp. nov. differs from this and other species of Ameroglossum , by having conspicuous membranous wings on the stem extending to the peduncle of the inflorescence and the pedicel (vs not or sparsely winged). Because of its green stems and leaves, A. alatum sp. nov. may also appear similar to A. bicolor sp. nov., although it differs by having its inflorescence in a simple dichasium (vs compound dichasium), winged peduncles and pedicels (vs partially winged) and the sepals not overlapping (vs sepals overlapping).

Etymology

The name is derived from the Latin adjective ʻ alatus ʼ, ʻwingedʼ, referring to the conspicuous wings on the branches, peduncles and pedicels.

Material examined

Type BRAZIL – Alagoas • Maravilha; 09°14ʹ39ʺ S, 37°19ʹ33ʺ W; 792 m a.s.l.; 21 Aug. 2012; E.M. Almeida & A.M. Wanderley 461; holotype: EAN!; isotype: K !.

Description

Saxicolous chamaephyte up to 80 cm, with secondary branching in the medial portion. Young branches greenish to slightly purplish, lustrous, quadrangular, conspicuously winged, glabrous; brownish when mature, slightly inclined, subquadrangular. Leaves opposite, decussate; leaf blade 3.5–6.0 × 1.5–2.5 cm, green with purplish margins, lustrous, elliptic to narrowly elliptic, slightly bullate; adaxial side glabrous; abaxial side with venation occasionally purplish, glabrescent with papillose trichomes, rarely aciculate; apex acute, rarely slightly caudate, reflexed; margin flat, occasionally revolute, ciliate. Inflorescence a simple dichasium. Peduncle purplish, frequently bifacial, subcylindrical, conspicuously winged, glabrescent, with papillose trichomes; primary peduncle 0.60–1.70 × 0.10–0.12 cm, secondary peduncle 0.20–0.80 × 0.06–0.07 cm. Pedicel 0.60–1.40 × 0.09–0.13 cm, greenish, frequently bifacial, glabrescent, with papillose trichomes; dorsal side conspicuously winged, ventral side with base slightly winged. Bracts 0.25–0.40 × 0.06 cm, slightly purplish, glabrescent, with papillose trichomes, margin glabrous. Calyx greenish, occasionally with reddish apex, abaxial side glabrous, adaxial side densely covered by papillose trichomes, margin glabrous; sepals lanceolate, dorsal ones 1.10–1.20 × 0.30–0.35 cm; lateral ones ca 1.0 × 0.2 cm; ventral ones ca 1.0 × 0.3 cm. Corolla 4.0– 4.5 cm long, orangish, externally pubescent, with papillose trichomes and/or glandular, internally glabrous; tube 2.8–3.3 cm long; upper lip 1.2–1.3 × 0.6 cm, slightly bilobate; lower lip 1.0–1.2 × 0.5 cm, inner perianth with filiform trichomes, white, lobes revolute, median lobe ca 0.10 × 0.13 cm. Stamens included, adnate to the middle of the corolla tube; filaments violet, ca 2.0 cm long; capsule ca 0.1 cm diam.; staminodium ca 0.6 cm long, adnate to the middle of the corolla tube, glabrous. Ovary 0.6–0.7 × 0.3 cm; style ca 4.6 cm long, exserted, glabrous. Capsule 1.5–1.7 × 0.7–0.9 cm, green. Seeds 0.10 × 0.05 cm.

Distribution

Currently known only from a single population on a granite outcrop near the city of Maravilha, in the Sertão Alagoano mesoregion, Alagoas State, Brazil. Elevation ca 790 m.

Ecology

As for the other taxa of Ameroglossum , A. alatum sp. nov. is restricted to granite outcrops, where it is probably pollinated by hummingbirds. Flowering and fruiting were recorded in August.

Population and threats

The population is composed of approximately 20 adult individuals, restricted to an area of approximately 3000 m ² on one of the tops of this granite outcrop. The small population demonstrates elevated homozygosity, suggesting a low genetic diversity, probably caused by a founder and/or a genetic bottleneck effect ( Wanderley et al. 2018).

Figures

Fig. 2. Reproductive branches and floral details of different taxa of the genus Ameroglossum Eb.Fisch., S.Vogel & A.V.Lopes. A. A. alatum sp. nov. B. A. asperifolium sp. nov. C. A. bicolor sp. nov. D. A. fulniorum sp. nov. E. A. genaroanum sp. nov. F. A. intermedium sp. nov. G. A. manoelfelixii L.P.Felix & E.M.Almeida. H. A. pernambucense Eb.Fisch., S.Vogel & A.V.Lopes. I. A. xukuruorum sp. nov.

Fig. 3. a–e. Ameroglossum alatum sp. nov. (Almeida & Wanderley 461). a. Reproductive branches. b. Stem. c. Leaf, abaxial side.d. Inflorescence. e. Corolla opened, showing the stamens.f–k. Ameroglossum asperifolium sp. nov. (Felix et al. 15160). f. Reproductive branches.g. Leaf, adaxial side.h. Inflorescence, showing the calyx. i. Flower. j. Flower, showing the stamens. k. Corolla opened, showing the stamens.