XIII. PAINTERIA Britton & Rose
Painteria Britton & Rose, N. Amer. Fl. 23: 35. 1928. Sp. typica: P. revoluta (Rose) Britton & Rose = Pithecolobium revolutum Rose.
Zygia ex parte sensu Mohlenbrock, 1963: 434.
Havardia sensu Nielsen, 1981: 184, fig. 2(4b), ex parte, quoad spp. amer
Microphyllous xeromorphic shrubs ±3-15 dm. Stipules of long-shoots lignescent and vulnerant, of short-shoots only acicular or subulate, rather closely imbricate. Lf-formula i—vi(—vii)/3—20; lf-nectary between proximal (or only) pinna-pair, rarely between 2 pairs, not on petiole proper; venation of lfts either palmate or almost simple. Inflorescence of (shortly spiciform) capitula arising from brachyblasts, the fls (unknown in P. revoluta) sessile or almost so; calyx campanulate or hemispherical ±1-3 mm; corolla ±3.5-6 mm, the lobes either ascending or recurving- spreading; androecium 28-76-merous, 6-12 mm, the tube either included or shortly exserted, bearing internally at base 5 small, sometimes obscure (or perhaps wanting) callosities; stipe of ovary 1-2.4 mm. Pods compressed but turgid, retrofalcate or retrocircinnate, the leathery valves biconvex over each seed, the cavity continuous; dehiscence tardy through both sutures; funicles straight or sinuous, not sigmoid; seeds plumply lentiform. — Spp. 3, of the Mexican Plateau, one of them disjunct in lowland Tamaulipas.
Painteria is feebly distinguished from Havardia by tougher-walled, falcately or further recurved pods, and by straight or sinuous but not distally sigmoid seed- funicles. The painterias are smaller treelets or shrubs that have the pronounced dimorphism of growth into long- and short-shoots and the deciduous microphyllidious foliage appropriate to (and presumably induced by) the arid climate of the Mexican Plateau.