Gwilymia A.G. Lima, Paula-Souza & Scalon, 2022

de Lima, Alexandre G., de Paula-Souza, Juliana, Ringelberg, Jens J., Simon, Marcelo F., de Queiroz, Luciano P., Borges, Leonardo M., de F. Mansano, Vidal, Souza, Vinicius C. & Scalon, Viviane R., 2022, New segregates from the Neotropical genus Stryphnodendron (Leguminosae, Caesalpinioideae, mimosoid clade), PhytoKeys 205, pp. 203-237 : 203

2. Gwilymia A.G. Lima, Paula-Souza & Scalon gen. nov.

Type.

Gwilymia paniculata (Poepp. & Endl.) A.G. Lima, Paula-Souza & Scalon ≡ Stryphnodendron paniculatum Poepp. & Endl., Nov. Gen. Sp. Pl. 3: 81. 1845).

Diagnosis.

Gwilymia is similar to Microlobius , but it differs in having branches and leaves without a garlic odour (vs. a strong garlic odour in Microlobius ); leaves with 2-4 (-6) pairs of pinnae (vs. 1-2 pairs of pinnae); each pinna with at least 3 pairs of leaflets (vs. a single pair of leaflets); extrafloral nectary present on the petiole or, in G. coriacea and G. fissurata , on the branch directly below the insertion of the petiole (vs. extrafloral nectary absent on the petiole and on the branch); inflorescence usually a compound thyrse (vs. always a simple thyrse); spikes 4-20 cm long (vs. 3-6 cm long); fruit an indehiscent (nucoid) legume 12-14 × 2-2.5 cm (vs. a follicle 6-7 × 1-1.5 cm), and brown or ochre seeds (vs. white seeds). Gwilymia also resembles Stryphnodendron , but it differs in leaves with 2-4 (-6) pairs of pinnae (vs. (3-) 5-32 pairs of pinnae in Stryphnodendron ), opposite leaflets, 2.5-16 × 1.5-8 cm (vs. alternate, 0.6-1.2 × 0.3-0.6 cm), inflorescence usually a compound thyrse (vs. always a simple thyrse).

Description.

Trees 2.5-40 m tall. Branches unarmed, not odoriferous, smooth, usually lenticellate, young shoots and leaves glabrescent, pubescent, or tomentose and covered with reddish granular trichomes. Stipules caducous. Leaves bipinnate, petiolar nectary 1 (absent in G. coriacea and G. fissurata ), 0.5-2 mm long, conical, lenticular or verruciform, positioned at the base or apex of the petiole; rachis 7-23 cm long, rachis nectaries 1-4, 0.5-2.5 mm long, conical, lenticular, patelliform or verruciform, inserted between the pairs of pinnae or just below them; pinnae in 2-4 (-6) opposite or subopposite pairs, rachillae nectaries 1-5, patelliform or verruciform, inserted between or just below the distal pairs of leaflets; leaflets in 3-5 opposite pairs, 2.5-16 × 1.5-8 cm, broadly-oblong, elliptic, ovate or obovate, not odoriferous, no tuft of trichomes at the midrib base. Inflorescence a compound thyrse (diplothyrsi or pleiothyrsi, a simple thyrse in G. coriacea and G. fissurata ), cymules in 2-5 spikes, spike 4-20 cm long (including peduncle and rachis), covered with ferruginous granular trichomes, inflorescence prophyll persistent (caducous in G. coriacea and G. fissurata ), floral bracts usually persistent. Flowers monoclinous; calyx pentamerous, gamosepalous, ca. 0.5-1 mm long, campanulate, cupuliform or tubular, puberulent or pubescent; corolla pentamerous, gamopetalous, 2-5 mm long, cohered for at least ½ of its length, campanulate or tubular, glabrous, pubescent, or tomentose; stamens 10, anthers with a caducous apical gland. Fruit an indehiscent, nucoid legume, sessile, 12-14 × 2-2.5 cm, curved, falcate or spiralled (straight to slightly curved in G. moricolor and G. racemifera ), laterally-compressed or sub-turgid, sparsely covered with ferruginous granular trichomes, valves woody or coriaceous, brown. Seeds elliptic, obovate, or orbicular, brown or ochre. Fig. 4 .

Geographic distribution and habitat.

Gwilymia species occur in the Amazon rainforest, seasonal forests and savannas of Bolivia, Brazil, French Guiana, Guyana, Suriname and Venezuela (Fig. 8 ).

Etymology.

Gwilymia honors Dr. Gwilym Peter Lewis, one of the Royal Botanic Gardens Kew’s most prominent botanists for his exceptional contributions to the advance of legume systematics.

Notes.

Gwilymia comprises seven species formerly placed in Stryphnodendron , all of which have 2-4 (-6) pairs of pinnae, opposite leaflets, 2.5-16 × 1.5-8 cm, compound thyrses (except in G. coriacea and G. fissurata ), and nucoid (indehiscent) legumes.

Figures

Figure 4. A, B Gwilymia coriacea: A flowering branch B fruit C, D G. fissurata: C detail of bark D fruit E, F G. paniculata: E flowering branch with young inflorescences F detail of the extrafloral nectary on the leaf rachis. Photos: Marcelo Simon.

Figure 8. Distribution of Gwilymia.