Cephalanthus glabratus (Spreng.) K.Schum. (Schumann 1889: 128)

Romero, Maria Florencia, Gonzalez, Ana Maria & Salas, Roberto Manuel, 2023, Sylvainia, a new monospecific genus within the subtribe Cephalanthinae (Rubiaceae, Naucleeae), Plant Ecology and Evolution 156 (1), pp. 85-111 : 85

2. Cephalanthus glabratus (Spreng.) K.Schum. (Schumann 1889: 128)

Figs 4 , 5

Buddleja glabrata Spreng. ( Sprengel 1824: 431).

Cephalanthus sarandi Cham. & Schltdl. ( Chamisso and Schlechtendal 1827: 610).

Type.

URUGUAY • Montevideo; 1814-1831; Sellow s.n.; lectotype (designated by Romero et al. 2021): HAL [HAL0107358]; isolectotypes: BR [BR0000005576456, BR0000005576784], E [E00505359], HAL [HAL0097791], L [L.0000206], M [M0187150] .

Description.

Shrub 3-5 m tall, much-branched; trunk with smooth bark, slightly striated longitudinally. Stems smooth, sparsely covered by lenticels, fragile and brittle, glabrous distally, rarely pubescent. Leaves 3(-4)-verticillate; pseudopetioles subcylindrical, with puberulous margin, elsewhere glabrous, 3-9 mm long; blades narrowly ovate or narrowly elliptic, glabrous, sometimes puberulous below, attenuate at base and acute at apex, subcoriaceous, slightly discolorous, 5-8 × 1-2 cm; veins 3-6 at each side, visible abaxially; domatia present as tufts of hair; stipules ovate-acuminate, membranaceous, green or reddish green when young, chestnut when falling off, pubescent on both sides, with dark colleters present at the apex and margin and light colleters on the lower half of the ventral (inner) side, intermingled with numerous trichomes. Inflorescences pedunculate, with peduncle 2-6 cm long, usually frondose-bracteate; bracts with dark colleters at the apex and margin; terminal glomeruli usually wider in diameter; anthesis usually regular; bracteoles spatulate, pubescent, with dark colleters at the apex. Flowers morphologically perfect, functionally male and female, sessile, both with a slightly cinnamon aroma; calyx 4-5(-7)-lobed; lobes broadly ovate or broadly triangular, obtuse, with edges pubescent, 0.37-0.7 mm long, with dark colleters at interlobular sinuses or apex; tube 0.7-1 mm long; corolla infundibuliform, 4-5(-7) lobed; lobes externally glabrous, with tiny appendages at the interlobular angle ending in dark colleters, rounded, 3.5-5.9 mm long, internally puberulous in male flowers and densely pubescent from the base to the upper third in female flowers, glabrous externally; tube glabrous internally and externally; stamens 4 or 5 (6 or 7), with filaments filiform, glabrous, 0.4-0.7 mm long; anthers subsessile, sagittal at the base, 1-1.4 mm long; style filiform, 5-7.5 mm long; stigma exserted at the end of anthesis, capitate in male flowers, bilobate in female flowers; nectariferous disc bilobed. Fruits schizocarp, obpyramidal or turbinate, sometimes angular and more or less irregular, glabrous, with pericarp coriaceous, reddish at the apex, 6-7 mm long. Seeds flat-convex 2.5-3 mm long; aril 1.5-2.5 mm long.

Distribution.

According to Romero et al. (2021), the species occurs in Argentina, Brazil, Paraguay, and Uruguay. It grows on low floodable land (lagoons, marshes, canyons, etc.), in flood plains of the main rivers in the region and their tributaries (Fig. 5 ).

Habitat and ecology.

According to Persia and Neiff (1986), the environments near the Uruguay River where Cephalanthus glabratus grows can be characterized as a particular type of seasonal wetlands or “bañados”, which are exposed to an alternation of dry and wet periods. It is composed especially of herbaceous species with scattered trees and shrubs of C. glabratus and Phyllanthus sellowianus Mull.Arg. ( “Sarandí blanco", Phyllanthaceae ). The authors called these environments "woody wetlands" or “bañados-bosques”. In coincidence with the seasonality and alternation of wet and dry periods, Romero et al. (2019) proposed that the structure of the leaf anatomy of Cephalanthus species shows adaptations to both hydromorphic (cuticle and thin cell walls, unistratified epidermis) and mesophilic habitats (large intercellular spaces and few trichomes), and tolerance to dry periods (heterobaric leaves).

Phenology.

It flowers profusely from August to October, declines towards December, and also in isolated specimens until May. Fruiting from the end of October to January, declining towards March.

Vernacular name.

Sarandí colorado ( Cabrera and Zardini 1978).

Uses and phytochemical aspects.

In traditional medicine, a decoction of the bark is a substitute for white sarandí ( Phyllanthus sellowianus ) and used for the treatment of diabetes. An infusion of the leaves is diuretic, depurative, and astringent ( Martínez Crovetto 1981; Romero et al. 2021).

IUCN conservation assessment.

The species should be considered as NT (Near Threatened) ( Romero et al. 2021).

Additional material examined.

ARGENTINA - Buenos Aires • Isla Martín García: Reserva Natural y Sitio Histórico, Isla Martín García, Talar de Arenal Central ; 24 Nov. 2005; Torres Robles 2315; MO • Mun. Berisso, Isla Paulino; 1905; Nianelli 90; SI • Quilmes; Nov. 1910; Jurado s.n.; SI • Mun. Tigre, Delta, Puerto Mirú; 4 Dec. 1931; Burkart 4541; SI. - Capital Federal • Belgrano; 22 Nov. 1927; Burkart 1682; SI . - Chaco • 1 de Mayo, Campo Antequera, Laguna La Mora; 1 Sep. 1971; Bacigalupo et al. 9529; MO, SI . - Corrientes • Mun. Colonia Pellegrini, Isla de vegetación flotante en la laguna Iberá; 5 Nov. 1973; Goodall & Tirel 255; SI • Mun. Concepción, pastizales con parches de plantaciones de matorrales forestales; 30 Nov. 1978; Renvoize 3686; CTES, MO • Mun. Empedrado, Estación Agronómica Tres Marías, próximo al Rio Parana ; 20 Mar. 1998; Schinini 34402; CTES, IAC . - Entre Ríos • Mun. Colón, Paraje La Calera, márgenes del Río Uruguay, desembocadura del arroyo Perucho Verna en Rio Uruguay ; 21-22 Dec. 1998; Simón 96; MO . - Misiones • Mun. Posadas, costas del Río; 16 Nov. 1905; Bertoni 1886; LIL • Mun. San Pedro, Parque Provincial Moconá; 27°08 ’00” S, 53°53 ’00” W; Seijo 849; CTES, G, MNES .

BRAZIL - Mato Grosso do Sul • Mun. Brasilândia, Rio Verde; 18 Oct. 1972; Hatschbach 30525; MBM, MO, NY; Mun. Rio Brilhante , Rio das Araras; 26 Oct. 1970; Hatschbach et al. 25247; NY, UEC • Mun. Mundo Novo, Porto Frangeli, Vargedos de inundação do Rio Paraná; 13 Oct. 1984; Hatschbach & Kummrow 48386; MBM, MO , US [ US 02370589]. - Paraná • Alto Paraíso; 14 Aug. 2015; Oliveira 2551; FURB, RB • Mun. Foz do Iguacu , Parque Nacional do Iguacu ; 16 Oct. 2015; Caxambu 7015; HCF • Mun. Guaiba , Entorno do Parque Nacional de Ilha Grande ; 26 Aug. 2009; Temponi 547; FUEL, UNOP. - Rio Grande do Sul • Mun. Alegrete , ca 51 km S de Alegrete na estrada para Caverá; 19 Nov. 2006; Queiroz 12571; HUEFS • Mun. Gravatai , vicinity of Gravataí, 20 km E from Canoas ; 20 m; 12 Dec. 1987; Tsugaru et al. B-2417; MO, NY. - Santa Catarina • Mun. Araranguá, Sombrio; Feb. 1946; Rambo s.n.; PACA [PACA31495] • Mun. Itapiranga, Forest above Rio Uruguai, Barra Macaco Branco ; 27°10'S, 53°46'W; 150-250 m; 18 Dec. 1964; Smith & Klein 14118; FLOR, HRB, MO, NY, R, RB, P , US [ US 02370590]. - São Paulo • Mun. Porto Primavera, Margem do Rio Parana , a montante da barragem de Porto Primavera ; 22°27 ’43.3” S, 52°52 ’25.9” W; 17 Oct. 1998; Bicudo 265; CGMS, PACA, UPCB .

PARAGUAY - Alto Paraná • 14 km W de Itaquyry; 12 Oct. 1995; Schinini & Caballero M. 30213; CTES. - Caazapá • 7 km W of Tavaí, swamp and cerrado scrub; 26°10 ’40” S, 55°34 ’47” W; 25 Nov. 1997; Zardini & Benítez 47646; AS, MO. - Canindeyú • Jejuí-mí, después del puente Carona, 49500/29450UTM, bosque ribereño bajo; 13 Sep. 1997; Marín 622; MO. - Central • San Lorenzo, Ciudad Universitaria, arroyo; 24 Oct. 1974; Arenas 931; MBM, MO. - Concepción • Paso Horqueta, Rio Aquidaban ; 19 Oct. 1984; Dure 389; MO • Paso Horqueta, Rio Aquidaban , gallery forest; 23°07'S, 57°20'W; 17 Mar. 1994; Zardini & Guerrero 39013; AS, MO. - Cordillera • Orillas del Lago Ypacarai ; Hassler 363; G. - Itapúa • Yacyreta Dam Island Reserve , eastern area, Aña Cua, clay soil with inundated savannas; 27°23 ’45” S, 56°39 ’08” W; 23 Oct. 1999; Zardini & Gamarra 51902; AS, MO. - Misiones • Santiago, Estancia La Soledad , Isla Corpiño; 21 Oct. 1957; Lourteig 2087; P, SI. - Paraguarí • Estero del Ypoa , 20 km W of Carapeguá, north of Pacheco , inundated savanna; 7 Jan. 1990; Zardini & Velázquez 17519; AS, MO. - San Pedro • Between Santa Rosa and Santa Barbara, inundated savanna; 23°50 ’26” S, 56°23 ’47” W; 29 Oct. 1996; Zardini & Guerrero 45505; AS, MO • Primavera, entre esteros y orillas húmedas; 11 Nov. 1957; Woolston 969; P, SI .

URUGUAY - Cerro Largo • Ruta 8, km 374, ayo. El Parao ; 32°44 ’34” S, 54°13 ’14” W; Seijo et al. 2714; CTES, SI . - Colonia • Colonia, Colonia Punta Gorda próximo a confluencia del Rio Uruguay con el Rio de la Plata , E de Rincón de Darwin; 33°54 ’57” S, 58°24 ’49” W; 24 Nov. 2007; Solis Neffa & Seijo 2121; CTES, ICN . - Rivera • Mun. Rivera, [damp] Cuñapirú, in silvula paludosa; 12 Jan. 1941; Rambo s.n.; PACA [PACA3996] . - San José • Herter 520; MO • Barra ; 10 m; Dec. 1926; Herter 769; MO . - Soriano • 17 Mar. 1940; Gallinal H PE-4361; MO .

Notes.

Romero et al. (2015) mentioned that C. glabratus lacks domatia. Later, they found that it has domatia as tufts of hair ( Romero et al. 2019).

Figures

Figure 4. Cephalanthus glabratus. A. Flowering branch. B. Domatia as tufts of hair. C. Axils of the secondary veins showing domatia as tufts of hairs. D. Partial inflorescence. E - G. Functionally female flower details. E. Flower. F. Open flower showing pubescence. G. Bilobed stigma and apical portion of the style. H - J. Male flower. H. Flower. I. Open flower showing pubescence. J. Capitate stigma and apical portion of the style. K. Dorsal view of schizocarp. L. Ventral view of schizocarp. M. Dorsal view of seed with aril. N. Subventral view of seed with aril. Drawn by Laura Simon.

Figure 5. Distribution map of Cephalanthus glabratus.