Monographs Details: Acacia paniculata (L.) Willd.
Authority: Irwin, Howard S. 1966. Contributions to the botany of Guiana. III. Leguminosae Mimosoideae. Mem. New York Bot. Gard. 15: 96-111.

Acacia multipinnata Ducke, Archiv. Jard. Bot. Rio de Janeiro 4: 31.

This species, a high-climbing thorny liana of the forest, is widely distributed in Amazonia and Guiana, and extends southward to Sao Paulo. In proposing A. multipinnata, Ducke implicitly recognized the marked differences between the material of the upper Amazon drainage and that of the lower. Careful consideration of 22 collections suggests one large heterogeneous population, with several minor characters varying more or less in relation to geography. Some five groups may be discerned, but none is sufficiently distinct to warrant formal recognition. These groups, together with the relevant exsiccatae, are summarized below:

Group A. Costa marginal; petiolar gland ovate, obconic, sessile; rachis glands restricted to apical ½ or 1/3 of the rachis, sessile or very short-stipitate, urceolate.

PERU. Ayaraca: Hoffmannsegg s.n. Type of A. paniculata Willd. BRAZIL. Rondonia (= “Guapore): Rio Madeira, Silva 427; Rio Branco: Rio Mucajai, Black 51-13348. BRITISH GUIANA. Sand Cr., Rupununi R., Forest Dept, of Br. Guiana 5643; Charwair Cr., Rupununi basin, A. C. Smith 2388; Kanuku Mts., A. C. Smith 3445. SURINAME. Copename R., Boschwasen 6270.

Group B. Costa subcentral; glands as in Group A.

BRAZIL. Amazonas: Manaus, Ducke 934. Para: Upper Rio Tapajds, Pires 2976; Upper Rio Capary, Krukoff 1146; Rio Trombetas, Ducke 11411. Rio Trom-betas, type of A. multipinnata Ducke; Belterra, Black 47-1886; Belem, Archer 8035 and Pires 2667.

Group C. Costa subcentral; petiolar gland as in Group A; rachis glands 1 between all or most pinna pairs, obconic, sessile.

BRAZIL. Amazonas: Manaus, Ducke 321; Tres Casas, Mun. Humayta, Krukoff 6340; Esperanca, Ducke 1026. BOLIVIA. Near La Paz, 700-800 m, Krukoff 10160.

Group D. Costa subcentral; petiolar gland urceolate, stipitate; rachis glands 1 between all or most pinna pairs, closely resembling petiolar gland but reduced in size.

BRAZIL. Para: Belem, Silva 175; Amapa: Rio Araguari, Pires, Rodrigues, & Irvine 51192.

Group E. Costa subcentral; petiolar gland and rachis small, stipitate, mutually similar. BRAZIL. Amapa: Rio Oiapoque, Irwin, Pires & Westra 48464. The last collection cited is a first report for A. paniculata in Amapa.