Desmodium triarticulatum Malme, Ark. Bot., Spec. Nov.
Creators: name: Lima, Laura Cristina Pires
name: Queiroz, Luciano Paganucci De
name: Tozzi, Ana Maria Goulart De Azevedo
name: Lewis, Gwilym Peter
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Fabales
Fabaceae
Desmodium
Desmodium triarticulatum

description: 30. Desmodium triarticulatum Malme, Ark. Bot. 18(7): 6. 1922. Meibomia caripensis var. triarticulata (Malme) Schindl., Repert. Spec. Nov. Regni Veg. 23: 354. 1928. Type:— BRAZIL. Rio Grande do Sul: Quinta pr. Oppidium Rio Grande, in ora dumetosa silvae paludosae ripae lacus Lagoa dos Patos, G.O.A. Malme II 1610 (holotype S!). Fig. 32.   
Erect, branched shrub, 0.5–1.5 m alt, with a xylopodium; stems not virgate, not slender, cylindrical, striate, glabrescent or sparsely uncinate, not glaucous; internodes 1.8–4.8 cm long. Stipules 3–5 × 1–1.5 mm, triangular, not auriculate, not amplexicaul, free from each other, apex caudate, margin ciliate, sparsely puberulous-uncinate, veins conspicuous, persistent. Leaves trifoliolate; petiole 5–14 mm long, cylindrical, sulcate, sparsely or densely uncinate; rachis 3–5 mm long; stipels 1–2 mm long, subulate, margin ciliate, puberulous-uncinate on the outer surface, persistent; leaflets concolorous, chartaceous, venation brochidodromous, primary and secondary veins prominent, tertiary veins inconspicuous on the abaxial surface, indumentum sparsely tomentose on the primary and secondary veins, tomentose or puberulous on the another veins on the abaxial surface, adaxial surface puberulous, rarely sparsely tomentose, uncinate hairs covering both surfaces, terminal leaflet 1.7–2.8 × 0.7–1.4 cm, elliptic,  
 DESMODIUM (LEGUMINOSAE, PAPILIONOIDEAE) IN BRAZIL   
 Phytotaxa 169 (1) © 2014 Magnolia Press • 89 90 • Phytotaxa 169 (1) © 2014 Magnolia Press   
 LIMA ET AL.   
oblong or rhombic, base cordate, oblique or obtuse, apex acute or subacute, lateral leaflets 1.2–2.4 × 0.7–1.3 cm, the same shape as the terminal leaflet. Inflorescence a terminal or axillary pseudoraceme or paniculate; the main axis longer than the adjacent leaves, (14.5–) 20.5–39 cm long, sparsely or densely uncinate, 2 flowers per node; primary bract 1.5–2.5 mm long, ovate-lanceolate, margin ciliate, puberulous-uncinate on the outer surface, caducous, veins inconspicuous on the outer surface; secondary bract 0.5–1 mm long, lanceolate, margin ciliate, puberulous-uncinate on the outer surface, caducous, veins inconspicuous on the outer surface; pedicel 6–11 mm long, densely puberulous-uncinate. Flowers 5–6 mm long, calyx bilabiate, tube campanulate, 1–1.5 mm long, tomentose and puberulous-uncinate on the outer surface; upper lip bifid, the 2 teeth joined more than ca. ¾ of their length, acute, ca. 0.1 mm long; lower lip trifid, lateral tooth subacute, ca. 1 mm long, central tooth subacute, ca. 1.5 mm long; corolla lilac, standard 5–6 × 3–4 mm, obovate, apex obtuse, maculate at the base, claw 1–2 mm long; wing petals 5–6 × 1–1.5 mm, oblong, apex obtuse, without callosities, claw 0.5–1 mm long; keel petals 5–6 × 1.5–2 mm, falciform, apex obtuse, with callosities, claw 1.5–2.5 mm long; androecium monadelphous, 5–6 mm long, vexillary stamen partially fused with the other from the base 1.5–2.5 mm long; ovary 3–4 mm long, tomentose, stipe 0.5–1 mm long, glabrous. Loment 1.1–2.4 cm long, stipe 1–2 mm long, glabrescent isthmus marginal, upper suture straight or slightly sinuate, lower suture sinuate; articles uniform 2–5, 5–7 × 3–4 mm, obovate-depressed, not tortuous, indehiscent, subcoriaceous, veins slightly conspicuous, densely uncinate. Seed 2.5–3.5 × 1.5–2 mm, oblong, hilum subcentral.  
 Selected specimens examined:— BRAZIL. Rio Grande do Sul: Bom Jesus: 13 Km de Bom Jesus para Vacaria, 5 January 1979, fl., fr., A . Zanin 82 (ICN); Jaquirana: RS 122, km 33, 1 March 2009, fl., fr., L . C. P. Lima et al. 548 (HUEFS). Santa Catarina: Lages: entre Índios e Palmeiras, 16 December 1967, fl., fr., A . Lourteig 2269 (K, L).   
 Distribution and Ecology:— Subtropical South America in Uruguay, Argentina and Brazil (Oliveira 1983, Izaguirre & Beyhaut 1998, Lima et al. 2010). In Brazil D. triarticulatum occurs only in the States of Rio Grande do Sul, and Santa Catarina, in areas of Rain Forest and Pampa. Collected in forest, along roadsides, and in grassland.   
 Conservation Assessment:— Least Concern (LC), not endangered (IUCN 2001).   
 Phenology:— flowering and fruiting from November to August.   
 Etymology:— from the Latin tri (= three) + articulatus (= articulate), probably in reference to the typically three articles of the loment.   
 Common Name:— amor-do-campo; pega-pega.   
 Taxonomic notes:— the combination of the following suite of characters: erect subshrub to shrub, semiamplexicaul and triangular stipules, petiole greater than leaf rachis in length, inflorescence paniculate, and fruit articles triangular, facilitates recognition of Desmodium triarticulatum. The leaflet shape (elliptic, oblong or rhombic) of this species is similar to D. uncinatum and D. affine, but those two can be differentiated by their ovate stipules (vs. triangular in D. triarticulatum), prostrate-ascending or decumbent habit (vs. erect in D. triarticulatum), and also by the androecium diadelphous, and the fruit articles oblong in D. affine (vs. androecium monadelphous, and articles triangular in D. triarticulatum).
description: Published as part of Lima, Laura Cristina Pires, Queiroz, Luciano Paganucci De, Tozzi, Ana Maria Goulart De Azevedo & Lewis, Gwilym Peter, 2014, A Taxonomic Revision of Desmodium (Leguminosae, Papilionoideae) in Brazil, pp. 1-119 in Phytotaxa 169 (1) on pages 89-91, DOI: 10.11646/phytotaxa.169.1.1, http://zenodo.org/record/10089817