Monographs Details: Jacaranda obtusifolia subsp. rhombifolia (G.Mey.) A.H.Gentry
Authority: Maguire, Bassett. 1978. The botany of the Guayana Highland--part X. Mem. New York Bot. Gard. 29: 1-288.
Discussion:2. Jacaranda obtusifolia Humboldt & Bonpland subsp rhombifolia (G. F. W. Meyer) A. Gentry, stat nov
Bignonia fdicifolia Anders., Trans. Soc. Arts 25: 200. 1807. Type. Surinam, Anderson sn (not seen), nom nud
Jacaranda rhombifolia G. F. W. Mey., Prim. Fl. Esseq. 213. 1818. Type. Surinam (not seen).
Jacaranda filicifolia D. Don, Edinb. Phil. Jour. 9: 266. 1823. Based on B. fdicifolia Anders.
Jacaranda filicifolia var.T puberula K. Schum., Mart. Fl. Bras. 8(2): 390. 1897. Type. Surinam, Kappler 1359 p.p. (not seen).
Jacaranda obtusifolia var rhombifolia (G. F. W. Mey.) Sandw., Kew Bull. 1953: 458. 1954.
In treating this plant as merely a variety distinguished from typical J. obtusifolia by its glabrous ovary, Sandwith had not realized the mutually exclusive distributions of these two entities (Fig 121). In view of its distinctive geographic range I propose elevation of the Guayana plant to subspecific rank. The new status is supported by the existence of an additional morphological character—the fruits of subsp rhombifolia are larger than those of subsp obtusifolia (5.5-6.5x (2.7-)3-3.6 cm (mean 5.9 x 3.3) versus 3.5-6(-7) x 2-3 cm (mean 4.7 x 2.5)). The change in rank is fortunate since var puberula has priority over better known var rhombifolia at the varietal level and the two are surely not distinct.
An unnamed related taxon from the Magdalena Valley of Colombia may ultimately prove a third subspecies of J. obtusifolia. It is not plotted on the distribution map.