Ameroglossum Eb.Fisch., S.Vogel & A.V.Lopes

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 : 4-6

Genus Ameroglossum Eb.Fisch., S.Vogel & A.V.Lopes

Feddes Repertorium 110 (7–8): 529 ( Fischer et al. 1999), here amended.

Type species

Ameroglossum pernambucense Eb.Fisch., S.Vogel & A.Lopez.

Description

Saxicolous, perennial chamaephytes, bases of stems slightly woody; plants up to 3 m; branching principally from the stem base, often secondarily branched irregularly along the stem. Young branches greenish to purplish, lustrous to dull, erect, quadrangular or cylindrical, thick, angular, often winged, glabrous, glabrescent, pubescent or villous, with trichomes aciculate, recurved, bifid or papillose; brownish to cinereous when mature, slightly inclined to incumbent, subquadrangular to cylindrical, not winged, glabrous, slightly lignified. Leaves sessile; opposite decussate or verticillate; leaf blade green to reddish or purplish, bifacial, rarely slightly cinereous, lustrous, rarely dull, lanceolate, narrowly elliptic, trullate, elliptic to ovate, smooth to strongly bullate; venation camptodromous; adaxial side with venation reticulate, impressed, glabrous to pubescent, with trichomes recurved or rarely papillose; abaxial side with venation reticulate, emergent, indumented principally on the venation, glabrescent, pubescent or villose, with trichomes aciculate, recurved, bifid ramified, glandular or papillose; base slightly decurrent in all species; apex acute, acuminate, slightly caudate to cirrhose, flat to recurved; margin serrate, flat to revolute, glabrous to ciliate, with trichomes recurved, rarely short aciculate. Inflorescence axillary, in simple or compound dichasia, rarely flowers single. Peduncles green to reddish, rarely bifacial, linear, cylindrical to subcylindrical, winged to wingless, glabrous, glabrescent, pubescent to villous, with trichomes aciculate, recurved, bifid or papillose. Pedicels green to reddish, frequently with base curved upwards, recurved after fertilization, subcylindrical, glabrous, glabrescent, pubescent to villous, with trichomes aciculate, recurved, bifid or papillose; dorsal side winged, ventral side varying from winged to wingless. Bracts green or tinged red, slightly cymbiform, inflexed; adaxial side glabrous to glabrescent, with trichomes papillose, rarely aciculate; abaxial side glabrous, glabrescent to pubescent, with trichomes aciculate, recurved, bipinnate or papillose; margin glabrous or ciliate, with recurved trichomes. Bracteoles present. Calyx green to purplish, rarely with apex reddish, pentamerous, gamosepalous, slightly asymmetrical; sepals lanceolate to broad-lanceolate, rarely ovate, dorsal sepal rarely overlapping lateral sepals, wingless or rarely winged by the prolongation of the wings of the pedicel; lateral abaxial side glabrous to pubescent with trichomes aciculate, recurved, bifid or papillose; adaxial side with trichomes papillose, rarely recurved; margin glabrous or ciliate, with recurved trichomes. Corolla scarlet to orange-yellow, sometimes with ventral or proximal third yellow, pentamerous, tubular, sometimes with wide base, zygomorphic, bilabiate, symmetrical; externally glabrous to pubescent, trichomes papillose, glandular, aciculate or recurved; internal side glabrous to glabrescent, trichomes papillose; upper lip bilobed to slightly bilobed, margin with violet border, revolute, principally at the apical portion; lower lip yellow, rarely with scarlet margins, slightly trilobed, with borders of the inner perianth densely pubescent, trichomes aciculate conical or filiform, white, yellowish white or violet; lobes revolute or involute, lateral lobes smaller; median lobe ovate to elongated. Stamens 4, didynamous, included or exserted, epipetalous, adnate to the distal median third of the corolla tube; filaments violet or white, glabrescent, covered by short glandular trichomes, principally on the distal third; anthers bithecous, thecae blackish, rounded; pollen blue, pulvinate; staminodium filiform, adnate from the proximal third to the middle of the corolla tube, glabrous to glabrescent, trichomes short glandular, rarely papillose. Ovary conical, laterally compressed, bilocular, pluri-ovulate, glabrous, rarely glabrescent, trichomes papillose and/or aciculate, base enveloped by an aneliform nectariferous disk; nectar transparent, abundant, sweet; style violet, terminal, exserted to enclosed, glabrous, rarely glabrescent, trichomes aciculate or papillose, principally on the proximal third; stigma capitate. Capsule green to purplish, conical, dehiscent; valves 2, pluriseminate, glabrous; calyx and style persistent. Seeds brownish, subreniform, longitudinal costae striate-undulate.

Ameroglossum is restricted to north-eastern Brazil (so far reported in the states of Alagoas, Paraíba, Pernambuco and Rio Grande do Norte). It comprises nine species and is morphologically similar to Cubitanthus , Catimbaua , Isabelcristinia and the African Stemodiopsis . A key to the species of Ameroglossum , Isabelcristinia , Catimbaua and Cubitanthus is provided below.

Note

The inflorescence was described by Fischer et al. (1999) as a frondose thyrse, which was based on the little material that was available to them at the time. However, this description of the inflorescence is incorrect. We have observed in cultivated material that when inflorescences are initiated, the plant produces inflorescence buds in the axils of leaves in the upper part of the main stems, which grow into inflorescences. These leafy stems can continue to grow for more than one flowering season. Therefore, the inflorescence is not a thyrse, but the inflorescences are axillary simple or compound dichasia.

Key to the species of Ameroglossum and related genera

1. Plants pendent or decumbent ............................................................................................................ 2

– Plants erect ........................................................................................................................................ 3

2. Leaves with arachnoid indumentum; flowers red, with tube larger than the lips ............................... ................................................................................... Catimbaua pendula L.P.Felix & E.M.Almeida

– Leaves with pubescent indumentum; flowers white, with tube smaller than the lips ......................... .............................................................................. Cubitanthus alatus (Cham. & Schltdl.) Barringer

3. Plants aromatic; leaves sticky, indumentum composed of glandular trichomes; corolla personate (masked) .......................................................... Isabelcristinia aromatica L.P.Felix & E.M.Almeida

– Plants without aroma; leaves not sticky, indumentum without glandular trichomes; corolla tubular ............................................................................................................................ ( Ameroglossum )...4

4. Leaves usually verticillate ................................................................................................................ 5

– Leaves opposite and decussate ......................................................................................................... 7

5. Lower lip of the corolla with inner perianth covered by filiform trichomes and with revolute lobes ............................ Ameroglossum intermedium E.M.Almeida, A.M.Wanderley & L.P.Felix sp. nov.

– Lower lip of the corolla with inner perianth covered by conical trichomes and with involute lobes ........................................................................................................................................................... 6

6. Branches puberulent; leaf blade with densely reticulated venation, puberulent on abaxial side ........ ..................................................... Ameroglossum pernambucense Eb.Fisch., S.Vogel & A.V.Lopes

– Branches glabrescent; leaf blade with sparsely reticulated venation, glabrous to glabrescent on abaxial side ................ Ameroglossum xukuruorum E.M.Almeida, Christenh. & L.P.Felix sp. nov.

7. Peduncles winged ............................................................................................................................. 8

– Peduncles without wings ................................................................................................................ 12

8. Young leaves rugose on the adaxial side, pubescent; calyx with two dorsal wings ........................... ............................. Ameroglossum asperifolium E.M.Almeida, J.M.P.Cordeiro & L.P.Felix sp. nov.

– Young leaves smooth adaxially, glabrous to glabrescent; calyx not winged .................................... 9

9. Branches dull, peduncle and pedicel pubescent, not glandular .......................................................... ............................ Ameroglossum intermedium E.M.Almeida, A.M.Wanderley & L.P.Felix sp. nov.

– Branches lustrous, peduncle and pedicel glabrous or sparsely pubescent with short, glandular trichomes ......................................................................................................................................... 10

10. Inflorescence a compound dichasium ................................................................................................. ..................................... Ameroglossum bicolor E.M.Almeida, A.M.Wanderley & L.P.Felix sp. nov.

– Inflorescence a simple dichasium ....................................................................................................11

11. Branches, leaves and calyx purplish; flowers with scarlet corolla ..................................................... ................................ Ameroglossum fulniorum E.M.Almeida, A.M.Wanderley & L.P.Felix sp. nov.

– Branches, leaves and calyx predominately green, flowers with orange corolla ................................. ..................................... Ameroglossum alatum E.M.Almeida, A.M.Wanderley & L.P.Felix sp. nov.

12. Plants densely branched; stem, leaves, peduncle, pedicel and calyx green; leaves principally ovate; flowers orange ..... Ameroglossum genaroanum E.M.Almeida, J.M.P.Cordeiro & L.P.Felix sp. nov.

– Plants sparsely branched; stem, leaves, peduncle, pedicel, and calyx purplish to slightly purplish; leaves narrowly elliptic; flowers scarlet .... Ameroglossum manoelfelixii L.P.Felix & E.M.Almeida