Sphinctanthus microphyllus K. Schumann, 1889

Salas, Roberto M., Florentín, Javier E. & Florentin, Mariela Nuñez, 2022, Sphinctanthus hasslerianus and S. microphyllus (Rubiaceae): taxonomic identity, lectotypifications and conservation assessment and chorology, Phytotaxa 545 (1), pp. 95-102 : 96-101

Sphinctanthus microphyllus K. Schumann (in Martius et al. 1889: 354).

Type:— BRAZIL. Mato Grosso: Cuiabá , “ Cuyaba, in umbrosis humidis ”, October 1827 (fl, fr), L. Riedel 1201 (Lectotype K! [barcode K000424497] designated here; isolectotypes BR! [barcode BR000000552339, left-hand branch], F! [barcode F0071137F]). ( Figs. 1 , 2 )

Sphinctanthus hasslerianus Chodat (1904: 170) , syn. nov.

Type: — PARAGUAY. Concepción: “ Prope Concepcion, in sabulosis ad fluminis ripam Paraguay ”, September 1901 –1902, E. Hassler 7297 (Lectotype G [barcode 00307480, 3 sheets], designated here; isolectotypes BM! [barcode 000549095], C!, F [barcode F0071135F], G! [barcodes G00307479 (2 sheets), G00307481, G00307482], P! [barcode 00753856], K! [barcode K000424498], MPU [barcode MPU021748], P [barcode P02273255], UC [barcode UC944181]) .

Shrub or treelet 0.5–3 m tall, with leaves and inflorescences at the tip of brachyblasts; bark smooth to slightly striated, greyish brown, with some irregularly shaped patches; terminal branchlets terete, 2–3 mm in diam., greyish beige, with distal internodes sparsely pubescent; older internodes with scarcely visible lenticel, sparsely pubescent. Stipules ovate, long acuminate, 2–4 mm long, puberulous or pubescent outside, with colleters intermingled with long hairs at the base inside, persistent, apex spinescent. Leaves short-petiolate; petioles 3–5 mm long; blades elliptic to obovate, 2.2–5.9 × 1–2.4 cm, base acute, apex obtuse, with or without a mucro, coriaceous, lustrous and glabrous adaxially, glabrous or only with dispersed hairs at the base abaxially, concolorous, bright green, dark olive-green when dry; secondary veins 3–7 on each side of midrib, curved towards the margins; domatia absent. Inflorescences uniflorous, subsessile to short pedunculate; peduncle 1.5 mm long, minutely puberulous. Flower buds pale yellow-green; corolla lobes contorted to the left. Flowers hermaphroditic, 5-merous without scent; pedicels 1 mm long, retrorse pubescent. Hypanthium subglobose to broadly obovoid, 4–5 mm long, minutely pubescent, retrorse; ovary 2-carpellar, 1-locular; placentation parietal; ovules numerous. Calyx subcoriaceous, pubescent; tube cupular, 1.8–3 mm long; lobes triangular to broadly triangular, 2.4–3.5 × 1.5–2 mm, retrorse pubescent inside, glabrous to puberulous outside. Corolla hypocrateriform, 35–60 mm long, somewhat fleshy when fresh, bright to pale yellow; tube funnel-shaped, subcylindrical, 17–48 mm long, densely antrorsely sericeous outside, with a ring of erect hairs near the base, the rest of the throat glabrous; lobes ovate, asymmetrical, 13–15 × 8–10 mm, apex obtuse, densely sericeous, hairs antrorse outside, glabrous inside. Stamens partially exserted; anthers subsessile, oblong, gradually narrower toward the apex, apex obtuse and then shortly mucronate, base obtuse. Pollen grains triporate. Style about as long as corolla tube at the final stage of anthesis, 20–48 mm long, glabrous, stalk smooth, 2-lobed; the lobes connivent, 3–5 ridged abaxially. Fruit globose or ovoid, fleshy, yellow-orange, brownish, with a crustaceous pericarp when dry, 15–20 × 15–18 mm, many-seeded. Seeds discoid to irregular, embedded in a juicy gelatinous pulp.

Distribution and ecology: —According to the collections plotted on the map of Figure 3 , Sphinctanthus microphyllus grows in the Pantanal Matogrossense, in the states of Mato Grosso do Sul and Mato Grosso, Brazil. All Brazilian collections came from flooded shrubby grasslands, in where it has been frequently mentioned as an aggressive weed (Allem 2587, 2599, 2526, CEN, CTES). In Bolivia it is known by only a few collections, all from Santa Cruz and Beni Departments. In this country, it grows in Cerrado, Chiquitano dry Forests, and savannas of Beni ecoregions. It also grows in seasonally waterlogged grasslands, frequently with Paspalum fasciculatum Willdenow ex Flüggé (1810: 69) (grass up to 1.6 m alt., Orellana & Beck 177, CTES & LPB). In Paraguay, it is restricted to the Paraguay River Basin, especially to the western part of the country. In dry Chaco, all collections came from Timané River, near or in the National Park Defensores del Chaco, along riverine vegetation. In addition to S. microphyllus, Santos (2020) recognised other five species for the Brazilian flora, of which three represents endemisms of the country: Sphinctanthus acutilobus Huber ( Huber 1914: 202) from Pará and Amapá, S. fluvii-dulcis in Minas Gerais, and S. insignis Steyermark (1981: 400) from Bahía.

Taxonomic notes: — Schumann (1889: 354–355) described Sphinctanthus microphyllus and cited the collections Riedel 942 and 1201. We here designate the specimen Riedel 1201 at K, barcode 000424497, as the lectotype of this name. The duplicates at BR (barcode BR000000552339), and F (barcode F0071137F) are isolectotypes. On the sheet where Riedel 1201 (BR000000552339) is mounted, is also mounted a specimen of Riedel 942 (barcode BR000000552372).

Chodat (1904: 170) described Sphinctanthus hasslerianus and cited the collections Hassler 7297 and Balansa 1751. The specimen Hassler 7297 at G with barcode G00307480, mounted on three sheets, is here designated the lectotype of this name due to the excellent state of conservation of the abundant material. The duplicates in BM, C, G, P, and K are isolectotypes. Sphinctanthus hasslerianus was provisionally treated as a synonymous of S. microphyllus in the context of the Flora of Brazil 2020 ( Santos 2020), therefore, it is formally listed as such.

Conservation status:—Least concern (LC). This species has an extent of occurrence (EOO) of 611.606 km 2, and an area of occupancy (AOO) of 156 km 2. It is known from 39 collection localities (GeoCAT points). According to the estimated EOO it should be classified as Least Concern (LC) and according to the estimated AOO it should be classified as endangered (EN). Sphinctanthus microphyllus grows associated with water bodies, as well as in humid areas of the open shrubby grasslands. Although it is subject to widespread threats, such as habitat loss, these threats do not represent any immediate threats for the species at the present (kml file available at https://figshare. com/s/63a1589a18c65bb13522). Based on IUCN guidelines, and the estimated EOO, the currently status should be considered as LC.

Common name: —“Rebenta-laço” (Portuguese, Brazil).

Additional specimens examined:— BOLIVIA. Beni: 150 m, sine data, M.H. Nee 34281 ( MO) ; Ballivián, Espíritu, en la zona de influencia del Rio Yacuma , sabana húmeda, Tajibal de Lucumos , 200 m, 17 October 1980 (fl), S.G. Beck 5148 ( CTES, LPB, MO, US) ; Ballivián, Estancia “La Asunta”, región suroeste del departamento del Beni , a 4 horas desde el puerto de Santa Rosa por el rio Yacuma , bosque de galería, 180 m, 14°14’40”S, 66°58’41”W, 5 July 2007 (fr), A. Antezana 951 ( MO) ; Yacuma, Espíritu, Río Yacuma , Llanos de Moxos , bosque de galería, 189 m, 14°08’S, 66°24’W, 18 February 1990 (fr), M. Moraes, J. Sarmiento & W. Hanagarth 11207 ( MO) ; Cercado , a 1 km de Puerto Almacén, sabanas benianas del Norte, pastizal de Paspalum fasciculatum de 1.6 m , 14°51’S, 64°57’W, 200 m, 3 June 1999 (fr), M.R. Orellana & S.G. Beck 177 ( CTES, LPB, MO) . Santa Cruz: Andrés Ibáñez , 6 km SE of San Lorenzo, on sandy ground, 420 m , 17°50’S, 62°50’W, 19 October 1996 (fl), C. Persson 353 ( MO, S); plain around Santa Cruz that is bound by the 700 m contour of the Andean foothills to the west, and the Río Grande to the east, 300 m , 17°44’30”S, 63°12’00”W, 17 November 1991 (fl), M.H. Nee 39997 ( LPB, NY) ; idem, 310 m, 17°44’30”S, 63°12’00”W, 22 November 1991 (fl), M.H. Nee 40205 ( LPB, NY) ; Ñuflo de Chávez, Ea. San Miguelito, 200 km NE de la ciudad de Santa Cruz ; puesto San Miguelito , llanura de inundación del Río San Julián , 1 km al E del puesto, 280 m, 17°01’S, 61°52’W, 28–29 July 1995 (fr), A. Fuentes 767 ( CTES, USZ) ; Sara, Laguna Juan Chulo , 16 km al NW de Santa Rosa del Sara, 250 m, 17°00’S, 63°44,6’W, 9–10 March 1996 (fr), A. Fuentes 1580 ( CTES, USZ) .

BRAZIL. Mato Grosso: Sine loco, 1833, C. Gaudichaud 298 (P); Cuyabá [Cuiabá], 8 November 1920 (fl), G.O.A. Malme s.n. (S-V726833); Barão de Melgaço, Fazenda Santa Lúcia, 4 October 1979 (fr), A.C. Allem 2526 ( CEN); Cáceres, estação Ecológica do Taiamã, 2 December 1980 (fl), J.J. Soares 6 ( SP); idem, 19 November 1980 (fl), G. Guarim Neto 318 ( UB); Poconé, PARNA do Pantanal, lado leste da sede do Parque, marmequezal com Aspilia latissima , 21 March 2001 (fl), A. Pott, A.L.B. Sartori, C.N. da Cunha, E.A. Silveira & L. Amorim 8622 ( CGMS, CPAP); Baia do Burro, 15 September 2001, E.A. Silveira C.N. da Cunha, H. Ferreira & E.C. Arruda 1707 ( CGMS); idem, lado oeste da Baía dos Burros, 15 September 2001 (fl), A. Pott, V.J. Pott, L.C.P. Lima, C.N. da Cunha, E.A. Silveira & E.C. Arruda 9390 ( CGMS, CPAP); idem, transpantaneira, 18 September 2001 (fl), G. Guarim Neto 318 ( UB); Faz. Campo Jofre, campo sazonalmente alagável, proximidades da rodovia Transpantaneira, Km 133, Poconé-P, 27 November 1993 (fl), A.L. Prado 2725 ( UEC); Faz. Ipiranga, 10 km south of Poconé; floodplains south of the farmhouses, 6 December 1991 (fl), M. Schessl 2488 ( UFMT, US); Morrinho, estrada da Integração, 28 December 1978 (fl), V. Neiden 34 ( NY); Faz. Santa Izabel, 19 November 1979, A.C. Allem 2587 ( CTES, CEN); idem, 10 November 1979 (fl), A.C. Allem 2599 ( CEN, CTES); Faz. Santa Isabel, Campo sazonalmente alagável, solo argiloso, compacto, 13 Km da rodovia Transpantaneira, Km 117-120, Poconé-Jofre, 25 April 1992 (fr), A.L. Prado, C.R. Soares, J. M. França & D. L. Prado 2805 ( UEC); Terceira parte ao sul do rio Pixaim, Transpantaneira MT-060, sub-região de Poconé, 11 November 2005 (fl), A. Pott & V. J. Pott 13533 ( CGMS, JPB); Faz. Uval, ao lado da transpantaneirapantanal, 08 September 1979 (fl), C.N. Cunha 10482 ( UEC); Porto Jofre, road to Santa Isabel from Jofre, 13 June 1979 (fr), G.T. Prance, J.B. Schaller & M. Becker 26184 ( CEN, NY); Transpantanal Highway, Fazenda Jofre, 15 November 1978 (fl), G. Schaller 270 ( NY); Fazenda Ecotrópica, 18 September 2001 (fl), E.A. Silveira 1739 ( CGMS). Mato Grosso do Sul: Corumbá, entre a Albuquerque e o Rio Paraguai, 90 m, 19°23’53”S, 57°23’21”W, 11 October 1985 (fl), J.F.M. Valls 9125 ( CEN); idem, Terras, 19°00’27”S, 57°35’13”W, 23 November 1987 (fl), J.A. Ratter, A. Pott, V. J. Pott, F. Martins & J. Tamashiro R6098 ( COR, CPAP, E, UEC); idem, margem esquerda do rio Paraguai em frente ao CEUC, 21 October 2005 (fl), J. Saab 11 ( COR); idem, estrada MS 228 de Corumbá ao Porto da Manga, entre segunda ponte y areial, planície do Rio Paraguai, pantanal, 90 m, 19°11”S, 57°28”W, 4 October 1984 (fl), A. Pott, G. L. Webster, V. J. Pott & C. A. Conceição 163 ( CPAP, CTES); idem, Rod. Br-262, 10–20 km W of Rio Paraguai, 22 October 1988 (fl), G. Hatschbach, M. Hatschbach & J.M. Silva 52494 ( CTES, G, INPA, MBM, NY, US); idem, Rio Paraguai, 27 November 2010 (fl), M.T. Oliveira, C.O. Dourado; T.S. Yule & R.H. Silva 43 ( CGMS); idem, 2 November 1993 (fl), C. Proença 993 ( CEPEC, ESA, NY, UB); idem, 19°00’S, 57°39’W, 1 January 1987 (fr), S.M. Salis, R. A. Mauro & W. M. 159 ( CPAP); idem, 17 June 1998 (fr), S.M. Salis & D. Calheiros 1037 ( CPAP); Morro no Amolar, Área da ECOA, 90 m, 17°53’S, 57°29’W, 1 November 2004 (fl), I.M. Bortolotto 1440 ( COR); idem, Fazenda Rio Vermelho, 28 October 1992 (fl), C.A. Conceição 2861 ( CGMS); “ Baia do Braz.”, 19 October 2002 (fl), G.A. Damasceno-Júnior, I.M. Bortolotto, I.H. Ishii, J.N. Nakajima, A. Sciamarelli, E.L.M. Assis, J.S. Velasques, P.V. Gonçalves, H.D. Cruz, G.E.O. Porfírio, D.P. Rodriguez, V.L. Nascimento, F.M. Alves & J.L. Sales 2557 ( CGMS, COR, HUFU, JPB, UEC); idem, beira da estrada, estrada direita, próximo do MENCK, direção Corumbá-Campo Grande, 30 November 2006 (fl), F. Matos-Alves, A.L.B. Sartori, C.A. Polido, L.C. Costa & F.M. Alves 247 ( CGMS); idem, sine loco, 22 November 1988 (fl), A. Pott, A. Boock, M. A. Araujo & G. A. Damasceno Júnior 4506 ( CPAP); Pantanal, 90 m, 28 September 1987 (fl), A. Pott, V. J. Pott, M. R. Araujo, M.P. Silva & A. Boock 3478 ( CPAP); idem, Miranda, Pantanal, 100m, 7 May 1987 (fr), A. Pott & C.J.A. Ferreira 2675 ( CPAP); idem, 90m, 4 October 1984 (fl), A. Pott, G. L. Webster, V. J. Pott & C. A. Conceição 1630 ( CPAP); Ladário, Baía Negra, 30 November 1993 (fl), C. Baracot & R. Culau 62 ( COR; UB); idem, Lagoa Negra, sine data, M.A.O. Bezerra s.n. ( COR).

PARAGUAY: Without locality, K. Fiebrig 1311 ( AS, SI) ; Colonia Risso, prope Rio Apa, 23 September 1893 (fl), G.O.A. Malme s.n. (UPS-V-726847); The River La Plata and Adjacent Countries, E. Palmer s.n ( US02494263 ) ; Alto Paraguay, June 2001 (fl), L. Pérez de Molas 7531 ( FCQ) ; Bahía Negra, Chaco Paraguayo , 18 November 1946 (fl), T. Rojas 13789 ( CTES, LIL) ; Parque Nacional Defensores del Chaco, Lagerenza, 7 km del cruce hacia Línea 1, bosque alto, 12 October 1998 (fl), M. Quintana 717 ( CTES, PY) ; Costa del Río Timané , 19°53’30”S, 60°52’05”W, vegetación xerofítica, 22 May 1996 (fr), F. Mereles & R. Degen 6399 ( CTES, FCQ) ; idem, selva ribereña del Río Timané , 5 April 1978 (fr), A. Schinini & E. Bordas 14892 ( CTES, MO) ; Isla Alta, Km 15, G. Schmeda 1554 ( US) ; Olimpo , November 1991 (fl), G. Schmeda 1464 ( US) .

Figures

FIGURE 1. Sphinctanthus microphyllus.—A. Portion of a branch with fruits and flower. B. Detail of a branch with flower in anthesis. C. Flower in anthesis, top view. D. Hypanthium and calyx lobes, top view (arrow). E. Flower bud. A: photo by Lidia Perez de Molas, downloaded with permission from Tropicos.org; B: photo by María Vera (reproduced with permission). C-E: photo by Rich Hoyer downloaded with permission from https://www.inaturalist.org.

FIGURE 2. Sphinctanthus microphyllus. A. Branch with flower buds. B. Node with stipule and base of petioles. C. Flower bud, side view. D. Flower bud, longitudinal section. E. Flower at early stage of anthesis, side view. F. Dissected corolla. G. Flower in anthesis. H. Hypanthium, calyx, and style. I. Longitudinal section of the ovary showing the disposition of colleters on internal side of the calyx. J. Immature fruit. A-B, F-I: from Beck 5148 (CTES); C-D: from Quintana 717 (CTES); J: from Pérez de Molas 7531 (FCQ)—Illustration by L. Simón and M. Nuñez Florentin (fruit).

FIGURE 3. Geographical distribution of species of Sphinctanthus in southern Brazil, Bolivia and Paraguay.