Parapiptadenia

Taxonomy

Parapiptadenia J.P.M. Brenan Kew Bull. 17: 228. 3 Oct 1963.

Subfamily: Mimosoideae.
Phylogenetic Number: 2.3.25.
Tribe: Mimoseae.
Group: Piptadenia.
Species Studied - Species in Genus: 3 studied; 6 in genus.

Description

Fruit: A legume; unilocular; 8–22 cm long; 1–3.6 cm wide; 0.2–0.4 cm thick; 2–9 times longer than wide, or more than 9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight to curved; not plicate; not twisted; symmetrical; broadly linear; not inflated; flattened; without beak; tapered at apex to rounded at apex; aligned with longitudinal axis of fruit; tapered at base to short tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous; seed chambers externally visible; margin irregularly slightly constricted to constricted; margin slightly constricted along both margins to constricted along both margins; margin without sulcus; margin plain; wing(s) absent; stipitate, or nonstipitate; with the stipe 7–16 mm long; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures (remaining attached to sutures); apical and down and medial and up and down; passive. Replum invisible. Epicarp dull; monochrome; reddish brown to brown; with surface texture uniform; glabrous; eglandular; without spines; not smooth; with elevated features; not veined, or veined (faintly); not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp absent. Endocarp present; visible; dull; opaque; monochrome, or mottled; tan; with brown overlay; smooth; without adhering pieces of testa; nonseptate (though valve somewhat pleated and tan between seeds); not exfoliating; entire. Seed(s) 7–11; length transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus 3–5 mm long; of 1 length only; filiform; S-curved. Aril absent.

Seed: 10–21 mm long; 2–15 mm wide; 0.1 mm thick; not overgrown; not angular; symmetrical; irregularly elliptic to oblong; flattened; with surface smooth; without visible radicle and cotyledon lobes; without hilar sinus; without umbo on seed faces; without medial ridge on each face. Cuticle not exfoliating; not inflated; not wrinkled. Testa present; without pieces of adhering epicarp; not adhering to endocarp; free from endocarp; glossy; not modified by a bloom; colored; monochrome; medium to dark brown; glabrous; smooth to not smooth; with elevated features and recessed features; rugose (on wing); pitted with small separate pits (on wing); chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) present (often erose); continuous around seed (not exceeding 6 mm in width). Raphe not visible. Hilum present; fully concealed; concealed by wing; without faboid split; punctiform; apical according to radicle tip but marginal according to seed length; flush; not within corona, halo, or rim. Lens not discernible. Endosperm present; thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to embryo. Cotyledons smooth; both outer faces flat; both the same thickness; both more or less of equal length; not folded; margin not entire 180 degrees from base of radicle; notched; similar at apex; not concealing radicle; notched at radicle; with lobes; with lobes not touching; without basal groin formed by lobes; with the interface division terminating at base of radicle; without margins recessed; inner face flat; glabrous on inner face. Embryonic axis straight; perpendicular to length of seed, or parallel to length of seed (perpendicular in 2 species and parallel in the other); without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; straight with embryonic axis; centered between cotyledons; less than 1/2 length of cotyledons. Plumule rudimentary; glabrous.

Distribution

Generic Notes

Lima and Lima (1984) studied the Brazilian four species of this genus, and their species count is used. They did not include P. excelsa (A.H.R. Grisebach) A.E. Burkart, an Argentinian species, in their study. Lewis (1994) described a new species in this genus, P. ilheusana G.P. Lewis, Bahia, Brazil, which was added to Lima and Lima's species count. This is the only mimosoid genus that has at least one species with basally notched cotyledons.