Mimosa perplicata L.M. Borges, 2014

Borges, Leonardo Maurici, Simon, Marcelo Fragomeni & Pirani, José Rubens, 2014, The census continues: Two new montane species of Mimosa (Leguminosae Mimosoideae) from Southeastern Brazil, Phytotaxa 177 (1), pp. 35-48 : 37-41

Mimosa perplicata L.M. Borges , sp. nov. ( Figs. 1 , 2.A–B , 3.A, E )

Mimosa perplicata has lax, sinuous branches that form a fuzzy crown; leaves with a laminar interpinnal projection, sometimes lacking; secondary veins as prominent as the primaries; glabrous corolla lobes; and fruits with a pedicel more than 5 × longer than wide. These characters distinguish it from M. setosa var. paludosa (Benth.) Barneby , which does not form entangled crowns; bears leaves with a spiculate interpinnal projection, sometimes lacking; has primary veins more prominent than the secondaries; corolla lobes always pubescent either with trichomes, filiform setae, or glandular setae, or a combination of these; and fruits with pedicel less then 4 × longer than wide.

Type:— BRAZIL. Minas Gerais: Joaquim Felício, Serra do Cabral , Estrada Joaquim Felício –Várzea da Palma, 10,3 km de Joaquim Felício, campo e afloramentos rochosos, 17º41’24.1” S, 44º11’43.6” W, 1025 m, 26 April 2012, fl., L.M. Borges et al. 647 (holotype SPF!, isotypes K!, NY!, P!, RB!)

Treelets to shrubs or (?)subshrubs up to 3 m, with a fuzzy crown formed by sinuous branches. Indumentum composed of simple trichomes, filiform setae and glandular setae with clavate head; branches, leaf axes, peduncles and fruits hirsute with filiform setae 2.2–6.2 mm long and fewer to sometimes absent glandular setae 0.4–2.5 mm long; leaf axes also pilose on adaxial surface with simple trichomes; stipules, leaflets and floral bracts acroscopic-ciliate with triple indumentum, floral bracts sometimes also with a few glandular setae on abaxial surface; branches and leaf axes armed with straight and broad-based aculei 2–6 mm long. Leaves (2)4–6-jugate; stipules 5.8–9.5 mm × 0.9–1.7 mm, lanceolate-ovate, acuminate, early caducous; petioles 3–4(–6.5) mm long, 0.8-1.2 mm diam., grooved on adaxial surface, sometimes restricted to the pulvinus 2–3 mm long; rachis 19–52 mm long, 0.6–1 mm diam., grooved on adaxial surface and with a spiculate to linear projection 0.7–1.2 mm long between each pinnae pair (sometimes absent), terminal projection 4.7–7 mm long, linear; basal rachillas 10–18 mm long, medial rachillas 13–22 mm long, distal rachillas 25–37 mm long, all 0.5–0.6 mm diam., 3–11 mm apart; leaflets 4.5–7 × 1.1–2 mm, 9–13 pairs on basal rachillas, 11–16 pairs on medial rachillas, 18–25 pairs on distal rachillas, narrowly-oblong, apex rounded to acute, base oblique, subcordate, rounded acroscopically, rounded–truncate basioscopically, 0.7–1.9 mm apart, 4–5 veins, prominent on abaxial surface, paraphyllidia 0.4–1.1 × 0.2 mm, subulate. Glomerules 8–13 × 7–9 mm, globose, 1- axillar to an almost fully developed leaf; peduncles (11–) 31–49 mm long; floral bracts 3.5–5.8 × 0.6–1.3 mm, acutespathulate, cymbiform, 3-nerved, veins prominent on adaxial surface; flowers 4-merous, diplostemonous; pedicel 0.1–0.2 mm long; calyx 0.3–0.9 mm long, cupulate, with a truncate rim or 4 irregular lobes 0.2–0.4 × 0.5–0.8 mm, triangular, ciliate with filiform setae 0.5–1 mm long and glandular capitate setae ca. 0.2 mm long; corolla 2.7–4.3 mm long, campanulate to infundibuliform, glabrous overall, lobes 1.1–1.5 × 0.9–1.3 mm, ovate, mucronate, 1-nerved, vein apex sometimes branching; filaments 9.8–15.5 mm long, glabrous, fused 0.1–0.9 mm at base, pink; anthers 0.4–0.6 mm long, glabrous; ovary 0.8–1.5 × 0.4–0.6 mm, narrowly oblong, tomentose with filiform setae 0.6–0.9 mm long, stipe 0.2–0.5 mm long, glabrous; style 7.5–15 mm long, glabrous; stigma porate, glabrous. Fruit a craspedium 29–40 × 9–10 mm, narrowly-oblong, papery, castaneous, apex acute, aristate, base cuneate; pedicel 3.4–5.5 mm long, ca. 0.7 mm wide; replum 0.8–1.4 mm wide; valves initially cracking only along margins together with separation from replum, but apparently breaking up entirely after seed dispersal into (3)7–9 articles, central ones 3–6 × 7.5–8.5 mm, monospermic, transversely oblong; seeds 5.8–6.4 × 3.6–3.9 mm, elliptic-ovate, foveolate, shiny dark brown, pleurogram present.

Additional specimens examined (paratypes): — BRAZIL. Minas Gerais: Joaquim Felício, Serra do Cabral , 28 July 1976, fl., fr., P.E. Gibbs et al. 2374 ( CEN!, UEC); 18 May 1977, fl., P.E. Gibbs et al. 5027 ( CEN!, UEC); campo rupestre, afloramentos rochosos, 900–1100 m, 21 December 1999, fl., fr., G. Hatschbach et al. 69421 ( MBM, NY!) ; 8 July 2001, fl., fr., A.Q. Lobão et al. 614 ( SPF!, VIC); campo rupestre, solo arenoso, 15 April 1996, fl., G. Hatschbach et al. 64817 ( HBG!, MBM, NY!, SPF!) .

Distribution: — Mimosa perplicata is endemic to campos rupestres with sandy soils and often rock outcrops of Serra do Cabral in the municipality of Joaquim Felício, Minas Gerais, Brazil ( Fig. 2 and 4 ).

Etymology: —The epithet is the Latin word for interlaced, “ perplicatus ”, and makes reference to the plant’s fuzzy crown, formed by its incurved, sinuous and somewhat lax branches ( Fig. 1 A , 2 A and B ). It is also allusive of its intricate relationship with the related sympatric species Mimosa paludosa , M. acroconica and M. caliciadenia .

Conservation status: —CR. GeoCAT analysis defined the area distribution of the species as less than 100 km 2, which, associated to the tendency for lost of habitat in the surroundings of Serra do Cabral State Park, where the species was collected, place it in the Critically endangered category. However, if more individuals are found in other areas of Serra do Cabral, particularly in protected areas of the park, its status can be updated to Endangered, since the range’s total area is less than 5000 km 2.

Notes: —Oldest collections of Mimosa perplicata were identified as M. setosa var. paludosa (e.g. Hatschbach et al. 64817), or M. acroconica (e.g. Gibbs et al. 2374, 5027; Hatschbach et al. 64817; Lobão et al. 614) both of which share a close relationship with this new species and are sympatric with it in Serra do Cabral. However, several characters, the main ones listed at Table 1 and pictured in Figures 2–3 , allow the distinction between them (a complete nexus table showing all variable features between the species is provided at http://dx.doi.org/10.7934/P1220). Particularly, the morphological plasticity of M. setosa var. paludosa poses problems for recognition of related taxa, but M. perplicata always presents glabrous corollas and stipitate fruits, while M. setosa var. paludosa has pubescent corollas and fruits almost completely sessile (see diagnosis). Lack of trichomes and the low number of glandular setae is also striking in M. perplicata , but, although both appendages are usually abundant in M. setosa var. paludosa , their concentration may vary widely amongst specimens. M. perplicata was probably previously confused with M. acroconica due the concentration of stipules in the apex of shoots, before their early fall. Those, however, are broader (more than 4 mm wide) in M. acroconica , which may also be set apart for being a treelet with incurved ascending branches ( Fig 2 E ), abundant villous indumentum ( Fig. 3 E ) and glandular setae with capitate (not clavate) head ( Fig. 1 E ). The fuzzy crown of M. perplicata resembles M. caliciadenia , which is endemic to the Diamantina plateau, at the main portion of the Espinhaço range. However, M. caliciadenia is different from the former species in bearing pin-headed glandular setae, aculeate foliar rachides, longer petioles and generally for lacking filiform setae on vegetative organs, although those may be randomly present. Further investigation is needed to find out if the species may also be a prostrate shrub, as indicated in Hatschbach et al. 69421 and Gibbs et al. 5027, or if habit information was mistakenly recorded. We suppose that this may be an indication that the plants can become early fertile, while still small, when their lax branches make them appear to be prostrate.

paludosa . See text for further information not provided and comments.

Figures

FIGURE 1. Mimosa perplicata. A. Habit. B. Branch. C. Adaxial surface of leaflet. D. Abaxial surface of leaflet. E. Branch detail showing the aculei and the indumentum composed by filiform and glandular setae. F. Detail of the rachis showing the interpinnal projection and triple indumentum of trichomes, filiform setae and glandular setae. G. Stipules at the apex of the branch. H. Glomerule with flowers in bud. I. Hermaphrodite flower. J. Calyx. Drawing by Marcelo T. Kubo.

FIGURE 2. Habits of Mimosa perplicata and related species. A–B M. perplicata. C. M. caliciadenia. D. M. setosa var. paludosa. E. M. acroconica and Dr. B. Loeuille.All photos by L.M. Borges.

FIGURE 3. Glomerules and branch indument of Mimosa perplicata and related species. A, E. M. perplicata. B, F. M. acroconica. C, G. M. caliciadenia. D. M. setosa var. paludosa. All photos by L.M. Borges.

FIGURE 4. Distribution map of Mimosa perplicata (▲) and M. serpensetosa (●).