Monographs Details: Sphinga
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. & Grimes, James W. 1996. Silk tree, guanacaste, monkey's earring: a generic system for the synandrous Mimosaceae of the Americas. Part I. Abarema, Albizia, and allies. Mem. New York Bot. Gard. 74: 1-292.
Discussion:X. SPHINGA Barneby & Grimes

Sphinga Barneby & Grimes, gen. nov., legumine recto planocompresso crasse papyraceo cum Havardia congrua, sed floribus elongatis, calyce profunde campanulato ante corollam emersam fusiformi acuto, corolla ipsa 11.5-27 (nec 3-5.5) mm longa, necnon androecio longissimo 4-9 (nec 0.91.5) cm longo diversa. — Sp. typica: S. platyloba (de Candolle) Barneby & Grimes = Acacia platyloba de Candolle. — Etymology: confected from Sphinx (Sphingidae), the putative pollinator + Tupi ingá, vernacular for several Mimosaceae.

Pithecolobium sect. Ortholobium sensu Bentham, 1875; 593, ex parte (spp. 84-86), lectotypo exclus.

Shrubs and trees, one sometimes sarmentose. Stipules of primary leaves subulate, spinescent. Lf-formula i-v/1-14; lf-nectary below midpetiole; the lfts opposite, the venation pinnate or (E. acatlensis) subpalmate. Capitula all or almost all arising from brachyblasts, the fls sessile or nearly so; fl-buds before exsertion of corolla flask-shaped, acute-acuminate; calyx cylindro-campanulate 5.5-12.5 mm; corolla narrowly trumpet-shaped 11.5-27 mm; androecium 34-176-merous, 4—9 cm, the tube usually far exserted; intrastaminal disc clasping stipe of ovary 0.5-1.3 mm tall. Pods broad-linear piano-compressed 6-10-seeded, the stiffly papery valves framed by sutures, the cavity continuous, dehiscence inert, through both sutures; seeds transverse on dilated, contorted or sigmoid funicle. — Spp. 3, two of arid or seasonally dry, tropical lowland and submontane (interior) Mexico, adjacent Guatemala, and NW South America (NE Colombia, NW Venezuela, Dutch W. I.), one endemic to Cuba.

The three species of Sphinga were all known to Bentham and grouped by him into an informal division of his Pithecolobium sect. Ortholobium, from which they were transferred by Britton and Rose to Havardia. The relationship to Havardia is not disputed, but these species differ collectively from the core of Havardia in the greatly elongated perianth (which recalls that of Macrosamanea in the context of Zygia), with long, silky corolla expanding at nightfall.

For notes on wood anatomy see discussion in Pithecellobium.