Coleostachys genipifolia Jussieu (1840: 329)

Almeida, Rafael Felipe De & Hall, Climbiê Ferreira, 2016, Taxonomic Revision of Coleostachys (Malpighiaceae), Phytotaxa 277 (1), pp. 77-84 : 78-83

Coleostachys genipifolia Jussieu (1840: 329) .

Type :— FRENCH GUIANA: Cayenne., s.d., Martin s.n. (holotype: P barcode P02428718 !; isotypes: BR barcode BR0000008577450!, F barcode V0062669F!, K barcode K000427026!, MICH barcode MICH1102137!, P barcodes P02428719!, P02428720!, P02428721!, P-JU barcode P00671745!, RB barcode 540728!). Fig. 1–4 .

Shrubs or treelets, 1.5–4 m tall, growth monopodial. Stems rugose, tomentose, hairs brown. Leaves decussate, entire, not reduced in inflorescences; stipules 1.8–2.2 × 4.7–5 mm, intrapetiolar, connate, deciduous, leaving a scar on stems; petioles 15.5–40 mm long, cylindrical, eglandular, sericeous to glabrescent at age, hairs brown; blades 29–59.5 × 6.5– 11.3 cm, plane, oblanceolate to spatulate, base acute to attenuate, margin plane; apex acuminate, adaxially glabrous, abaxially sericeous only along the veins, eglandular; venation brochydodromous, primary veins adaxially impress, abaxially prominent, secondary veins 29–32 pairs, proximally opposite, distally alternate, adaxially impressed, abaxially prominent, tertiary veins adaxially inconspicuous, abaxially conspicuous. Spikes axillary to terminal; main axis 9.5–22.7 cm long, cylindrical, smooth to striated, tomentose, basal node bearing 1-pair of stipule-like bracts, 1.5–4 cm long, smooth, sparsely sericeous to glabrous, enclosing apex of shoots before elongation; cincinni 16–33, cincinni 1-flowered, proximally opposite, distally subopposite; bracts 5–7 × 4–4.5 mm, ovate, sessile; apex acute, tomentose, eglandular; peduncles sessile; bracteoles 2–3 × 1.5–2 mm, ovate, sessile; apex rounded, tomentose, eglandular. Flowers 11.3–15 mm diam., floral buds 4–7 × 3–6 mm, obovoid to sub-globose; sepals not concealing petals in floral bud, 4–5 × 3–4 mm, ovate, shortly connate at base, margin repand, apex rounded, adaxially glabrous, abaxially sericeous; hairs brown, eglandular; petals white, cucullate, margin erose; posterior petal erect, limb 7.5–8 × 8.5–9 mm, depressed ovate, adaxially glabrous, abaxially sericeous centrally; claws 2.5–3 × 0.8–1 mm, canaliculate, adaxially glabrous, abaxially sericeous; lateral petals patent, limb 6–7 × 6–7.5 mm, widely ovate, adaxially glabrous, abaxially sericeous centrally; claws 2.5–3 × 0.5–0.6 mm, canaliculate, adaxially glabrous, abaxially sericeous. Stamens 10, all fertile, free; filaments 2.5–3.2 mm long, whitish, arched at apex, densely tomentose at base; hairs straight-basifixed; connectives very reduced and inconspicuous; anthers yellow, linear-lanceolate to lanceolate, apex acute, base cordate, locules 3.5–5.5 × 1.2–1.5 mm; pollen sacs parallel, sparsely sericeous, dehiscing by 1 apical pore. Ovary 3-carpelate, free, all fertile, 1.5–1.8 × 0.5–0.8 mm, hirsute; styles 3, 5–7.5 × 0.2–0.35 mm, slightly bent inwards, subulate, basal, whitish; stigma apical, subulate. Schizocarp composed by 3 un-winged mericarps (cocci), borne on a flat torus; cocci 6–12 × 5–8 mm, subspheroidal, tapered towards the areole, smooth, indehiscent, thin-walled, brittle; areole 2–2.5 × 0.9–1 mm, piriform. Seeds 7–8 mm × 5–6 mm, sub-globose, flattened; embryo bent inwards.

Specimens analyzed:— BRAZIL. Amapá: sin. loc., 17 November 2011, fl., Bastos 263 ( IAN, RB). Maranhão: Vila Rondon, 14 August 1976, fl., Pinheiro 65 ( IAN). Pará: Alto Rio Capim , 26 March 1949, fl., Fróes 24147 ( IAN) ; Candirú-Açú , 28 August 1957, fl., Fróes 33618 ( IAN) ; Ilha do Breu , 19 September 1987, fl., Prance 1353 ( IAN, NY) ; Moju , 4 November 1923, fl., Ducke 228 ( P) ; loc. sit., Juruá Florestal , 22 October 2001, fl., Martins 13 ( IAN) ; Paragominas , 1 December 2010, fl., Oliveira 573 ( IAN) ; Parauapebas, Serra dos Carajás , 19 December 1989, fr., Rosa 637 ( IAN) ; Região do Candirú-Açú, Rio Capim , 28 August 1957, fl., Fróes 33618 ( IAN) ; Rio Capim , 25 March 1949, fl., Fróes 24121 ( IAN) ; Rio Moju , 16 April 1957, fl., Fróes 33922 ( IAN) ; loc. sit., lugar Fábrica , 1 December 1955, fl., Pires 4593 ( IAN) ; loc. sit., December 1953, fl., Pires 4583 ( IAN) ; São Domingos do Capim , 25 November 1980, fl., Ramos 736 ( INPA) ; São Miguel do Guamá, km 149 Belém-Brasília Road , 26 January 1960, Oliveira 422 ( IAN) ; Serra dos Carajás, 28 June 1976, fl., Ribeiro 1395 ( IAN) ; Tailândia , 20 January 2011, fr., Costa-Neto 2985 ( MFS, MG) ; loc. sit., 20 January 2011, fl., Costa-Neto 2967 ( MG) ; Tomé-Açú , 1 January 1978, fl., Nascimento 385 ( MG) ; loc. sit., 22 October 1979, fr., Silva 5073 ( MG) ; Tucuruí , 19 June 1978, fl., Rosa 2424 ( IAN, MG) ; loc. sit., 14 November 1968, fl., Daly 1331 ( IAN, INPA, MG, NY) ; Ulianópolis , 1 December 2000, fl., Secco 1089 ( MG) .

Distribution, ecology and phenology:— Coleostachys genipifolia grows in the understory of lowland forests (“terra firme” forests) of Eastern Amazon in Brazil (states of Amapá, Maranhão and Pará) and French Guiana ( Fig. 4 ). Most known collections are from the state of Pará in Brazil, which might suggest this region is its center of diversity. Flowering occurs from July to April and fruiting in December.

Conservation status:— Coleostachys genipifolia has an EOO of 528,403.414 km ² which fits with the IUCN category Least Concern. Nonetheless, when comparing its distribution range to a land use shapefile from state of Pará (its center of diversity) it becomes clear that most forest remnants from eastern Pará are being converted into farming and livestock land ( Fig. 4 ). Biodiversity of the Eastern Pará state has been historically threatened by several human activities, such as farming (soybean crops), livestock, logging and mining (especially on Carajás Mountains) (IBGE 2015). All these activities require clearing of the rainforest reducing understory habitats occupied by C. genipifolia .

Etymology:— The genus name Coleostachys derives from the Greek words sheath (koleos) and spike (stachys), due to the resemblance of a sheath of epipetiolar stipules and bracts at the base of spikes ( Anderson et al. 2006). The epithet genipifolia makes reference to the similarity of its leaves with those of the genus Genipa Linnaeus (1754: 87) , Rubiaceae .

Discussion:— Coleostachys genipifolia is the single Neotropical genus of Malpighiaceae with poricidal anthers. This feature is only known from two Paleotropical Malpighiaceae genera, Acridocarpus Guillemin & Perrottet (1831: 123) and Tristellateia Thouars (1806: 14) . Since those genera represent three unrelated lineages of early diverging Malpighiaceae ( Davis & Anderson 2010) , we can assume that poricidal anthers emerged independently at least three different times in the family. Acridocarpus and Tristellateia are both confined to Africa and Madagascar, with a single species of the later also widespread in Southern Asia ( Anderson et al. 2006). Their ancestors represent different dispersal events from the Neotropics to the Old Word ( Davis et al. 2001; Davis et al. 2002a; Davis et al. 2002b; Davis & Anderson 2010), and both diversified at ca. 30 Mya ( Davis et al. 2014). Interestingly, the same pattern is observed for Coleostachys , with its ancestor starting to diversify at ca. 30 Mya somewhere in the Neotropics ( Davis et al. 2014). This scenario leads us to believe that poricidal anthers might probably have emerged in Malpighiaceae due to similar selective pressures related to specific pollinators. However, our assertion is merely speculative and only future studies on pollination biology of those genera might shed some light on this question.

Figures

FIGURE 1. Coleostachys genipifolia: A. Habit, B. detail of the leaf and inflorescence, C. detail of the inflorescence axis, D. detail of a flower bud, E. detail of a flower (photos by A. Cardoso).

FIGURE 2. Coleostachys genipifolia: A. fruiting branch, B. detail of a inflorescence, C. floral bud in lateral view, D. flower in frontal view, E. detail of a stamen, F. gynoecium, G. detail of a cocci (MG202875).

FIGURE 3. Holotype of Coleostachys genipifolia.

FIGURE 4. Distribution of Coleostachys genipifolia in Northern South America, highlighting land use in the state of Pará, Brazil.