Monographs Details: Sipanea pratensis var. dichotoma (Kunth) Steyerm.
Authority: Maguire, Bassett. 1967. The botany of the Guayana Highland--Part VII. Mem. New York Bot. Gard. 17: 1-439.
Family:Rubiaceae
Description:Distribution and Ecology - The Guianas, Venezuela, Colombia, northern Brazil and Trinidad. TRINIDAD. Piarco Savanna, Broadway s.n.; Piarco Savanna, Britton, Coker & Rowland 86. FRENCH GUIANA. Riviere Mana, Halle 741. SURINAME. Berthoud-Coulon 176; Zanderij I, savanne B, Lanjouw & Lindeman 3270; Wilhelmina Gebergte, Zuid Rivier, 3°20'N, 56°49'W-3°10'N, 56°29'W, on granite rocks near rapids, 2 km above confluence with Lucie Rivier, alt 220 m, Maguire, Schulz, Soderstrom & Holmgren 54056; granitic outcrop in forested hills 9 km N of Lucie and 12 km W of Oost riviers, Wilhelmina Gebergte, 3°36'-3°41'N, 56°30'-56°34'W, alt 275 m, Maguire, Schulz, Soderstrom & Holmgren 54223; vicinity Kayser Airstrip, 25 km above confluence with Lucie Rivier, Wilhelmina Gebergte, Zuid Rivier, 3°20'N, 56°49'W-3o10'N, 56°, alt 270 m, Maguire, Schidz, Soderstrom & Holmgren 53958; savanna ca 2 km N of Lucie Rivier, 2 km W of Oost Riviers, 3°20'N, 56°49'W-3°32'N, 56°26'W, alt 225 m, Maguire, Schulz, Soderstrom tb Holmgren 54214; Tibiti Savanne, Lanjouw tb Lindeman 1601, 1618; granitic plateau in line from Pakapaka (Saramacca River) to Ebbatop (v. Asch- v. Wijcks-Range), near Km 8, J. & P A. Florschiitz 1309; on granitic rocks at Brokonoto Falls in the Saramacca River, Florschiitz 1214; Sanderij, Savanna 11, Maguire & Stahel 23663; Hostmann 663 (photo of type of Sipanea trichantha) ; Hostmann 507; near Kayser Airstrip, 45 km above confluence with Lucie Rivier, Wilhelmina Range, Zuid Rivier, 3°20'N, 56o49,W-3°10'N, 56°29'W, alt 270 m, Irwin, Prance, Soderstrom & Holmgren 55963, 55946. BRITISH GUIANA. Kaieteur Plateau, Potaro River, alt 395 m, Alston 549; moist savannahs, Schomburgk 15. 95; savanna, basin of Rupununi River, near mouth of Charwair Creek, lat ca 2°35'N, A. C. Smith 2390; Kaieteur Savanna, Hollister s.n.; frequent between Ayanganna and Chinowieng, Mt. Ayanganna, Pakaraima Mts., alt 1000-1200 m, Maguire, Bagshaw & C. K. Maguire 40639; moist marginal land between savanna and marsh, St. Ignatius, Rupununi River, Harrison 1283; junction of Alazaruni and Cuyuni rivers, at Kalacoon, Graham 101; Mazaruni River settlement, C. D. tb R. C. Mell 226; southern Pakaraima Mts., Kamana Savanna, pebbly red laterite, en route to Ivopinang Falls, Maguire, C. K. Maguire & Wilson-Browne 45974-A; stream bank, 1 mi N of Lethem, Rupununi District, Irwin 570; sandy bank of creek, 2 mi S of Arajoui, Cook 88; swale S of Lethem near Takutu river, Rupununi District, Irwin 620, 622; Skull Point, near Bartica, Ramsammy 13; Waramadong, Kamarang River, Upper Alazaruni District, Pinkus 21; along the Berbice-Rupununi Cattle Trail, Berbice or Demerara County, Waruni-Ituni savannahs, Abraham 27, 129; along Potaro River, Tumatumari," Gleason 44, 45; Tapacooma rest house, Jenman 7829; Alazaruni River, Jenman 5453; Bartica, Jenman 4723; Cuyuni river, sides of portage road at Lower Camaria Landing Sandwith 655; Kaieteur Falls, Potaro River, De La Cruz 4448; upper Rupununi River, near Dadanawa, Lat 2°45'N, De La Cruz 1800; Mora Landing, Aloruka River, Pomeroon District, De La Cruz 975; Waini River, Northwest District lat 8 20 N, long 59 40 De La Cruz 3573; between the Demerara and Berbicerivers, lat about 5°50'N, De La Cruz 1578, 1603, 1604; vicinity of Bartica on the Essequibo River, lat 6°25'N, De La Cruz 1860; Wanana River Northwest District, lat 7°45'N, long 60°15'W, De La Cruz 4047; Kamakusa, upper Alazaruni River, long about 59°50'W, De La Cruz 2765.VENEZUELA Delta Amacuro-downstream from mouth of Yarakita River, Rio Amacuro, Sierra Imataca Ven Brit. Guianan frontier, alt 65-80 m, Steyermark 87445; Monagas: between Montana de Aguacate and Colorado, along Rio Caripe, E of Caripe, alt 700-800 m, Steyermark 62237; alrededores de Caripito, Pittier 14375; selva mas alia del pueblo de Cachipo, Campo de Quiriquire, Lasser & Vareschi 3999; swampy margins of Laguna Grande just S of La Pica, E of Maturin, Wurdack & Mona-chino 39556; Bolivar: more or less level forest in vicinity of Quebrada Agua Linda, 8-11 km E of campamento Nuria, E of Hato de Nuria, near pica 35 and 106, Altiplanicie de Nuria, alt 550 m, Steyermark 86515; savanna-chaparral between Hato Corumo and Las Chicharras, northeast of Tumeremo, Steyermark 86248; moist sandy openings along small stream in savana, between Ciudad Bolivar and Rio Caroni, alt 100 m, Steyermark 57576; terreno pantanoso y en el margen de los morichales, Guayapo, Bajo Caura, Williams 11770, 11953; en la savana de Guayapo, Bajo Caura, Williams 12086; savanna bordering morichal northwest of camp, 5 km from Hato de Nuria, east of Miamo, Altiplanicie de Nuria, alt 400 m, Steyermark 88332; Zulia: sabana, Perija, alt 30 m, Hermano Gines 1569; Amazonas: sabanas de Atures, alto Orinoco, Williams 15914 (topo-type of Sipanea dichotoma) ; sabana de Puerto Ayacucho, alt 100 m, Williams 13450; sabana, Puerto Ayacucho, Williams 12979. COLOMBIA. Magdalena: savanna, La Jagua, alt 100 m, Haught 3587; Baja Magdalena, Dawe 445; sabana, 17 km N of El Banco, on road to Chimichagua, Haught 2216; Cundinamarca: Caqueza, alt 1810 m, Garcia Barriga 8466; Vaupes: sabana, San Jose del Guaviare, alt 240 m, Cuatrecasas 7411; Rio Metica, Puerto Lopez, alt 380 m, Cuatrecasas 3567; Ocana, May 1846-52, Schlim 548 (type of Sipanea colombiana). BRAZIL. Rio Branco: savanna below airstrip, Serra Tepequem, alt 700-800 m, B. & C. K. Maguire 40147 Amazonas: in vicinibus Barra, Prov. Rio Negro, Spruce 994

Discussion:

Sipanea dichotoma H.B.K., Nov. Gen. & Sp. 3: 397. 1820.

Sipanea trichantha Miq., Linnaea 18 : 293. 1844.

Sipanea colombiana Wernh., Jour. Bot. 55: 174. 1917.

This variation embodies the great mass of specimens in which the lateral axes of the inflorescence are more or less elongate, producing a subsecund monochasial or dichasial appearance, and with the fruit cylindrical-oblong, longer than broad, usually 4-8 mm long. The corolla-lobes may be completely glabrous without or partly pubescent along one or both outer margins. Likewise, there is great variability in the pubescence of leaves, stems, and capsules. There is also variation in corolla-length as well as in length of mature capsules. These variations are considered here as forms of var. dichotoma as elucidated in the key to varieties and forms of S. pratensis.

Sipanea dichotoma H.B.K. is the earliest name to be applied to the series of variable taxa related to S. pratensis. The type of 5. dichotoma was collected from the Atures rapids of the Orinoco in Venezuela and is described as having villous stems, pilose-sericeous ovary, pilose capsule, pilose calyx, and shortly petiolate leaves which are villous-sericeous on both sides. Although no specimen or photo of the type has been seen, the topotype collection of Williams 15914 would indicate a plant having densely pubescent vegetative parts and with the corolla-lobes pubescent on the outer margins. This is the commonest and most widely distributed variation, likewise, and would include Miquel’s S. trichantha described from Suriname.

Within the variation shown by S. dichotoma with pubescent corolla-lobes, there appear two main trends, (1) in which the calyx-lobes are setaceous and slightly elongate, and the inflorescence is more branched, and (2) in which the calyx-lobes are shorter and less setaceous, and the inflorescence is less branched. However, no correlation has been found within these variables and all have been merged into S. pratensis var dichotoma.

Distribution:Guyana South America| French Guiana South America| Venezuela South America| Colombia South America| Brazil South America| Trinidad and Tobago South America|