Galactia decumbens (Benth.) Chodat & Hassler (1904: 900)

Ceolin, Guilherme B. & Miotto, Sílvia T. S., 2013, Synopsis of the genus Galactia (Phaseoleae, Papilionoideae, Leguminosae) in Brazil, Phytotaxa 134 (1), pp. 1-26 : 5-6

5. Galactia decumbens (Benth.) Chodat & Hassler (1904: 900) Type: — BRAZIL. Minas Gerais: Caxoeiras do

Campo, Clausen 106 (isotype NY![photo]). ( Figs. 3A , 5D ).

Basyonim: Collaea decumbens Bentham (1849: 515) Type:— BRAZIL. Minas Gerais : Caldas, Regnel 64 (isotype US n.v.).

Galactia decumbens f. suberecta Burkart (1971: 790) . Type: — BRAZIL. Goiás: Catalão, Irwin 25440 et al. (holotype NY!). syn. nov.

Galactia bullata (Bentham) Taubert (1894: 368) var. bullata . syn. nov.

Basyonim: Collaea bullata Bentham (1862: 149–150) . Type: — BRAZIL. Goiás, Gardner 3663 (isotype BAB n.v.) .

Galactia bullata var. magnifolia Burkart (1971: 767) . Type: — BRAZIL. Goiás: Contraforte Central, Irwin 25154 et al. (holotype SI!). syn. nov.

Prostrate to ascending (or sometimes erect) herbs; leaves unifoliolate; inflorescences longer than the leaves that subtend them; flowers 10–14 mm long, aggregated at the inflorescence apex, with wine red coloured insect guides on the outside surface of the standard petal.

Selected specimen: — BRAZIL, Mato Grosso: Chapada dos Guimarães, 15º28'S, 55º48'W, 15 January 2009, G. B. Ceolin 170 (ICN) .

Distribution: —Endemic to Brazil (DF, GO, MG,, MS, MT, SP).

Habitat and ecology:—Cerrado biome, in open grassland, shrubland, along forest edges, and on rocky outcrops, at elevations from 600–1250 m, in clay and sandy soils.

Notes: —the characteristics of the type of Galactia bullata var. magnifolia fit almost perfectly the characteristics of G. decumbens , namely the unifoliolate leaves, large inflorescences, and flowers congested at the inflorescence apex, with wine red coloured insect guides on the outer surface of the standard petal; the former differs mainly by its erect habit and the number and size of its flowers. These differences include the criteria used in this study to infer reproductive isolation, since differences in flower size and density are traits thought to influence the behaviour of pollinators and prevent gene flow ( Worley et al. 2000). However, as far as we could observe, we were unable to find any specimen in our fieldtrips, even in the region where the type was collected. In addition, there are no other exsiccatae of Galactia bullata in herbaria, except the type, and even Burkart admitted that he saw no material of G. bullata var. bullata . Therefore, due to lack of further evidence, the most parsimonious attitude we can take is to regard G. bullata as an aberrant form of G. decumbens and propose its synonymization. Additionally, Burkart (1971) described G. decumbens f. suberecta based on the ascendant habit of some individuals. Habit in Galactia species can be very variable and recognition of a separate taxon therefore does not seem appropriate.

Phenology:— Flowering and fruiting from November to May.

Figures

FIGURE 3. A. Galactia decumbens. B. Galactia dimorpha. C. Galactia jussiaeana. D. Galactia peduncularis.

FIGURE 5. A. Individual of Galactia marginalis showing the inflorescence few-flowered and shorter than the subtended leaf. B. Small population of Galactia glaucescens showing terminal inflorescence (senescent; arrow). C. Detail of Galactia eriosematoides showing the nodose aspect of the inflorescence as well as the wine red coloured insect guides on the outer surface of the standard petal. D. Two individuals of Galactia decumbens showing the inflorescence larger than subtended leaf and flowers aggregated at the apex.