Monographs Details: Sipanea acinifolia Spruce ex Sprague
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 - Venezuela and Amazonian Brazil. VENEZUELA. Bolivar: en el margen de zanjas y en lugares cenegadas, Guayapo, Bajo Caura, Williams 11917; sitios bajos y periodicamente anegados en la sabana de El Tigre, Williams 13411; en morichales de las sabanas de Purucuy, Tamayo 3450; Caicara, Sprague 383; Cerros Las Piedras en el Carmen, Velez 2546; Guarico: margenes Cano Rialito, a unos 30 km este de Calabozo, via Cazoiba, Aristeguieta 4592; Amazonas: orillas del Rio Orinoco en los alrededores de San Fernando, Molina & Barkley 18.V.161; Puerto Ayacucho, Holt & Blake 774; at Santa Barbara at junction of rios Orinoco and Ventuari, Maguire, Cowan & Wurdack 30811, 34479 BRAZIL. Para: in vicinibus Santarem, Spruce 329 (lectotype of S. acinifoha).

Discussion:

Type. Vicinibus Santarem, Prov. Para, Brazil, Nov-March 1849-50, R. Spruce 329 (lectotype).

In describing this species Sprague took up Spruce’s manuscript name. Collections cited were Sprague 383 from Caicara on the Orinoco in Venezuela, and Spruce 3562 from Maypures on the Orinoco in Colombia, and the range was given to include also the “Lower Amazon” (undoubtedly referring to the Spruce 329 collection from Santarem, Brazil.

At first Wernham (Kew Bull. 1914: 64. 1914) identified another Sprague collection from Caicara (Sprague 7) on the Orinoco River in Venezuela as S. acinifolia, but later (Jour. Bot. 55: 172. 1917) concluded that the Sprague 7 collection represented an undescribed species to which he assigned the name Sipanea spraguei. At this time Wernham reduced S. acinifolia Benth. ex Sprague to synonymy under S. veris Moore, identifying Spruce’s Santarem collection con-specifically with that of the Spencer Moore 435 specimen from Mato Grosso, and the latter was cited by Wernham as the type collection of S. veris. In the present treatment, however, I have taken the plant having the glabrous exterior of the corolla-tube of Spencer Moore 435 (the type of S. veris) as representing a different and distinct species from that having the exterior of the corolla-tube pubescent, as shown by Spruce 329 from Santarem, with the name S. acinifolia applied to the latter. This conforms to the original description by Sprague.

The character of leaf pubescence has been found to vary greatly, with leaves densely strigose on both sides as in Sprague’s original description of S. acinifolia, and as represented by Spruce 329 from Santarem and by Velez 2546 from El Carmen, Venezuela. This leaf variation comprises populations in which the upper surface of the leaves is glabrate to sparsely appressed-pilose above and sparsely appressed-pilose along the nerves beneath, as well as populations with a slightly greater degree of pilosity on the lower surface with glabrity confined to the upper surface. However, there is little or no demarcation within these intergradations, and it is believed at this time, until further collections are available, justifiable to encompass the variability of leaf pubescence in S. acinifolia as one taxon.

Some variability also exists in leaf shape and stem habit, from prostrate or decumbent stems to those having flowering stems ascending or erect, and in leaves varying from narrowly lanceolate-elliptic with obscure petioles, as in Spruce 329, to those having petiolate, ovate leaves with petioles 2 mm long. The size of the leaves varies as greatly in S. acinifolia as it does in S. veris (including S. spraguei).

Distribution:Venezuela South America| Brazil South America|