Amorimia rigida (A. Juss.) W. R. Anderson, 2006

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 : 22

Key to the species of the Amorimia rigida complex

1a. Leaves lanceolate elliptic to narrow-elliptic, velutine to glabrous at age, with 10–16 pairs of secondary veins; bracts and bracteoles reflexed; sepals erect with revolute apex at anthesis, glands turning ocher, petals adaxially entirely velutine, filaments pubescent at apex, styles uncinate at apex; samaras with dorsal wing depressed ovate ................................................... Amorimia andersonii

1b. Leaves ovate to elliptic to wide-elliptic to orbicular, sericeous-velutine to glabrous at age, with 8 or fewer pairs of secondary veins; bracts and bracteoles parallel; sepals appressed to the androecium with straight apex at anthesis, glands turning brown or red, petals adaxially proximally glabrous, filaments glabrous, styles truncate at apex; samaras with dorsal wing obtrapezoidal or triangular 2

2a. Petals turning red at post-anthesis, posterior petal 2-glandular at base of limb; samaras with dorsal wing obtrapezoidal with rounded angles..................................................................................................................................................... Amorimia candidae

2b. Petals turning orange at post-anthesis, posterior petal eglandular; samaras with dorsal wing triangular or obtrapezoidal bearing a projection at apex...............................................................................................................................................................................3

3a. Leaves with a pair of glands near margin or near base; claw of the posterior petal up to 1 mm long; stamens opposite the anterior sepal, posterior-lateral sepals and posterior petal longer than those opposite lateral petals .................................... Amorimia rigida

3b. Leaves with a pair of glands near or at base; claw of the posterior petal more than 1 mm long; stamens opposite petals longer than those opposite sepals..........................................................................................................................................................................4

4a. Claw of the posterior petal larger than 0.5 mm wide, lateral petals patent at anthesis, anthers pubescent at apex, connectives and base; samaras with dorsal wing triangular......................................................................................................... Amorimia pellegrinii

4b. Claw of the posterior petal up to 0.5 mm wide, lateral petals reflexed at anthesis, anthers pubescent only at base; samaras with dorsal wing obtrapezoidal.................................................................................................................................................................. 5

5a. Leaves conduplicate, not bullate; peduncles exceeding bracts at anthesis; glands turning brown at post-anthesis, anterior-lateral petals divergent; samaras with dorsal wing bearing an aciculate projection at apex ........................................... Amorimia coriacea

5b. Leaves plane, bullate; peduncles not exceeding bracts at anthesis; glands turning red at post-anthesis, anterior-lateral petals overlapping; samaras with dorsal wing bearing two triangular projections at apex .................................................... Amorimia velutina