Cephalanthus occidentalis L. (Linnaeus 1753: 95)

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

4. Cephalanthus occidentalis L. (Linnaeus 1753: 95)

Figs 7 , 8

Cephalanthus occidentalis var. brachypodus DC. (de Candolle 1830: 539) - Type: USA - Texas • Entre el Río de la Trinidad y Bexar [San Antonio]; Jun. 1828; Berlandier 1737; holotype: G; isotypes: BM, YU [YU065576].

Cephalanthus occidentalis var. californicus Benth. ( Bentham 1849: 314). - Type: USA - California • Sacramento; Hartweg 1765; holotype: LD [LD1361264]; isotypes: BR [BR0000005577118], GH [GH00104738].

Cephalanthus berlandieri Wernham ( Wernham 1917: 175) - Type: USA [Mexico] - Texas • Bexar [Bejar]; Berlandier 1620; holotype: BM [BM000606675].

Cephalanthus hansenii Wernham ( Wernham 1917: 176) - Type: USA - California • Amador Co., Crow Point; 1500 ft; Jul. 1895; Hansen 1163; lectotype (designated by Ridsdale 1976): BM [BM000606652]; isolectotypes: L [L.2583462], LE [LE00017272], US [US00130640]; syntype: MEXICO • Chihuahua, San Diego Canyon, Sierra Madre; 6400 ft; Sep.; Jones s.n.; BM.

Cephalanthus occidentalis f. lanceolatus Fernald (Fernald 1947: 181) - Type: USA - Virginia • Southampton, North of Courtland, upper border of sandy and peaty shore of Darden’s Pond; 15-16 Nov. 1946; Fernald, Long & Clement 15357; holotype: GH [GH00092512].

Cephalanthus occidentalis subsp. californicus (Benth.) A.E.Murray ( Murray 1982: 19) - Type: same as for Cephalanthus occidentalis var. californicus .

Cephalanthus naucleoides DC. (de Candolle 1830: 539) nom. illeg. - Type: same as for Cephalanthus occidentalis .

Type.

COUNTRY UNKNOWN • s.col. s.n.; lectotype (designated by Reveal in Jarvis et al. 1993): LINN [LINN118.1].

Description.

Shrub or small tree up to 3 m tall, much branched. Stems glabrescent or puberulous, with numerous lenticels. Leaves 2 or 3 per node, pseudopetiolate, pseudopetiole with pubescent margin, 7-26 mm long; blades elliptic, narrowly ovate, or oblong, base acute, apex acuminate, glabrous, puberulous or pubescent adaxially, sometimes only pubescent on mid-vein abaxially, discolorous, 5-18 × 2-8 cm; principal lateral veins 6-10 on each side, visible abaxially, leaf domatia present, pockets, internally pilose; stipules ovate-acuminate to narrowly triangular, tardily deciduous, dark colleters present at the apex and margins, light colleters on the ventral (inner) side, intermingled with trichomes. Inflorescences pedunculate; peduncle 3-10 cm long, bracteate, dark colleters present at the apex and margin, bracteoles spatulate, puberulous, dark colleters present at the apex. Flowers perfect, calyx 4(-5)-lobed; hypanthium cupuliform, glabrous to densely pubescent at the base, 0.6-1.5 mm long; lobes obtuse, 0.3-0.6 mm long, externally puberulous, internally densely pilose, dark colleters present at the interlobular sinuses; corolla hypocrateriform, 4(-5)-lobed, 5-9(-12) mm long, lobes obtuse or ovate, internally with a longitudinal band of hairs, densely disposed, externally glabrous, 1-2 mm long, dark colleters present at the interlobular sinuses, tube internally and externally glabrous; stamens 4(-5), filaments filiform, glabrous, anthers large, sagittate, subsessile, 1-1.3 mm long; style filiform, 6-10 mm long; stigma capitate and exserted at flower maturity. Fruits narrowly obovate, glabrous, 5-7.5 mm long. Seeds 1.5-2.3 mm long; aril 1.4-1.8 mm long.

Phenology.

Flowering from March to August, exceptionally from September to November. Fruiting from October to December. In its southernmost distribution (southern USA, Mexico, and Caribbean), it is possible to see flowers and fruit throughout the year.

Vernacular names.

Buttonbush, common buttonbush, button-willow, buck brush, honey-bells, button ball, and riverbush.

Distribution.

Native to the Northern Hemisphere, in Belize, Canada, Cuba, Guatemala, Honduras, Mexico, and USA (Fig. 8 ).

Habitat and ecology.

Cephalanthus occidentalis occurs in places that are temporary flooded or waterlogged, such as the banks of rivers, streams, or wetlands. It has been cultivated in botanical gardens in Europe since colonial times for its profuse flowering and resistance to cold. In the USA and Mexico, it is common in gardens because of its rusticity and showy flowers.

Additional material examined.

BELIZE • Maskall; 17°52 ’42” N, 88°18 ’47” W; 5-20 m; 10 Mar. 1934; Gentle 1254; MO • Stann Creek, ca 1 mile WSW of Hopkins, sea level, thickets in open marshland; 16°51 ’17” N, 88°17 ’51” W; 17 Apr. 1976; Proctor 35797; MO .

CANADA - Quebec • Ile Perrot; 1908; Victorin s.n.; AMD [AMD116817] • Missisquoi Bay Area , près Montreal ; 23 Aug. 1959; Hegnauer 1959-775; L [L.2853429] • Rigaud, comté de Vaudreuil; 26 Jul. 1934; Roy 333 7; L [L.2853435], SI • Rigaud, comté de Vaudreuil; 23 Aug. 1935; Roy 4075; L [L.2853447] . - Ontario • Deep Bay, Sparrow Lake, wet shores, often in water; 7 Aug. 1935; Kirk 142; L [L.2853442]. - Ottawa • Pontiac Station , 30 miles west Hull, north shore of Ottawa river ; 28 Aug. 1948; Breitung 7327; SI .

CUBA - La Habana • Border of Laguna Ariguanabo ; 2 Jul. 1914; A. León 4337 ; US [ US 00794830, US 00794844]. - Las Villas • On Gerhartz farm, 12 km E of Cascajal, shrub on edges of playa; Jun.-Aug. 1941; Howard 5584; MO, NY. - Pinar del Rio • El Sablalo, Finca Sabanalamar; 22 Dec. 1937; Killip 32295; MO .

GUATEMALA - Petén • Quexil Turicentro , bordering the lake, in high forest; 16°55 ’10” N, 89°49 ’11” W; 5 Feb. 1970; Contreras 9596; MO • Sayaxche; 16°31 ’35” N, 90°11 ’22” W; 5 May 1942; Steyermark 46270; MO .

HONDURAS - Atlántida • Tela, Triumfo de la Cruz, 1.4 km N of the Tela-Ceiba Hwy. on the road to El Triumfo de la Cruz ; 15°48'N, 87°24'W; 5 m; 17 Apr. 1994; Brant & Hazlett 2879; MO . - Gracias a Dios • Brus Laguna, Isla de Pájaros, Laguna Rapa , al sur[este] de Brus Laguna, nivel del mar; 15°43 ’36” N, 84°27 ’27” W; 5 m; 17-27 Apr. 1971; Nelson & Hernández Meza 1064; MO .

MEXICO - Chihuahua • Vicinity of Aldama ; 15-17 May 1908; Palmer 234; K, MO , US [ US 00869798]. - Coahuila • Sierra Encantada at Rincon de Maria , about 5 miles S of Hacienda La Babia, with base camp at 1130 m, and going up canyon to the horizontal roadway that passes across the limestone rincón, these from the horizontal roadcut to 3.5 miles NE of the path up; 28°29'N, 102°01'W; 1700 m; 22 Aug. 1998; Henrickson et al. 20621; MO. - Durango • Jun.-Sep. 1896; Palmer 201; MO. - Guerrero • Juan R. Escudero, Tierra Colorada, carretera a la Presa Gral. Figueroa, antes de Puente Río; 17°07 ’40” N, 99°31 ’30” W; 350 m; 2 May 1965; Kruse 1479; MO. - Michoacán • La Huacana, presa Gral. Francisco J. Múgica, alrededores de la presa, puente de piedra; 19°03 ’35” N, 102°00 ’25” W; 333 m; 4 Sep. 2010; Cortés Flores & Carmen Coba P. 46; MEXU, MO. - Tabasco • Macuspana, Laguna El Gusano, aprox. 1 hora por lancha del sitio llamado el bordo Hormiguero, al norte de Cd. PEMEX, borde de la laguna; 18°05 ’48” N, 92°23 ’41” W; 7 m; 16 Mar. 1998; Novelo R. & Ramos V. 2293; MO. - Veracruz • Las Choapas, 11 km del entronque Las Choapas con la carretera Cardenas-Coatzacoalcos; 18°03'N, 94°06'W; 50 m; 14 Apr. 1973; Orozco S. 103; MO .

USA - Arizona • Maricopa Co.; 628 m; 6 Jul. 2012; Markings & Butler 3959; ASU, SI • Maricopa Co., Bosque Nacional de Tonto ; 33°47.93'N, 11°29.49'W; 25 Jun. 1999; Landrum 9539; CTES. - California • Clear Lake , Goosenek point, in pebbly shore of lake; 1320 ft; 28 Jul. 1974; Thorne 45065; L. - Illinois • Jackson Co. ; 37°35 ’08” N, 89°27 ’44” W; 110 m; 21 Oct. 2014; Nee 61696; MO, SI. - Missouri • Saint Louis City, Missouri Botanical Garden’s Monsanto Research Center campus, by southwest corner of building, south of chiller equipment; 6 Sep. 2017; Taylor 12977; CTES, MO. - New Jersey • Burlington Co. ; 23 Jul. 1981; Ley 42199; CTES. - New York • Bronx; 40°52 ’03” N, 73°52 ’34” W; 16 m; 6 Jun. 2006; Nee 54470; SI. - North Carolina • Biltmore, swamps and borders of streams; 19 Jul. - 30 Sep. 1897; Biltmore herbarium 1890; L [L.2853436]. - Ohio • Mantua, road 34, near old Coyle’s Farm; 14 Sep. 1963; Bruyne s.n.; L [L.2853437]. - Texas • Aransas Pass Co. , on N. Mc Campbell Road, between Rabbit Road and Jacoby Lane; 3 Jun. 1998; Fryxell 5137; CTES • Comanche Co. , near Cache; 25 Jun. 1913; Stevens 1319; SI. - Washington DC • Potomac River bij Chain Bridge; 6 Sep. 1952; Holthuis 519; L [L.2853446]. - Wisconsin • Richland Co. ; 210 m; 14 Jul. 1978; Nee 16308; SI • Richland Co. , 2 miles NW OF Blue River , floodplain of the Wisconsin River, along the channel (usually with flowing water) flowing into Garner Lake ; 43°11 ’55” N, 90°36 ’00” W; 204 m; 27 Sep. 2014; Nee 61662; SI .

Notes.

Cephalanthus occidentalis has a profuse synonymy, especially with names published by Constantine S. Rafinesque between 1828 and 1838. Rafinesque published four new species ( C. acuminatus , C. obtusifolia , C. obtusifolius , and C. pubescens ) and four infraspecific taxa ( C. occidentalis var. macrophylla Raf., var. Cephalanthus occidentalis macrophyllus Raf., var. Cephalanthus occidentalis obtusifolius Raf., and var. Cephalanthus occidentalis pubescens Raf.), all synonymized under C. occidentalis by Ridsdale (1976). As yet, no type specimens were found that support these names, and therefore, they were not included in the synonymy.

Figures

Figure 7. Cephalanthus occidentalis. A. Flowering branch. B - D. Variation in leaf form. E. Pocket with domatia as tuft of hairs. F. Partial inflorescence, in bud stage. G. Perfect flower. H. Unfolded corolla. I. Dorsal view of schizocarp. J. Ventral view of schizocarp. K. Longitudinal section through fruit and seed. L. Ventral view of mericarp with opening in apical region (slight manual pressure was exerted to provoke the opening). M. Subventral view of seed with aril. N. Dorsal view of seed with aril. O. Lateral view of seed with aril. Drawn by Laura Simon.

Figure 8. Distribution map of Cephalanthus occidentalis and C. salicifolius.