Parkia

Taxonomy

Parkia R. Brown In Denham et Clapperton, Narr. Travels Africa 234. 1826.

Subfamily: Mimosoideae.
Phylogenetic Number: 2.1.02.
Tribe: Parkieae.
Species Studied - Species in Genus: 16 studied; ca. 40 in genus.

Description

Fruit: A legume; unilocular; 8.5–60 cm long; 1.5–9 cm wide; 0.2–2 cm thick; 2–9 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 0.5-coiled; not plicate; twisted, or not twisted; asymmetrical; broadly linear to oblong; not inflated; compressed to terete; without beak; short tapered at apex to rounded at apex; short tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; when fresh fleshy, or coriaceous to ligneous (or tough-fleshy upon drying); seed chambers externally visible, or invisible; margin slightly constricted to not constricted; margin without sulcus; margin plain; wing(s) absent; stipitate, or substipitate; with the stipe 0.5–100 mm long; with all layers dehiscing, or indehiscent; splitting along suture(s). Dehiscence of valves along 1 suture (ventrally), or both sutures; apical and down; passive. Replum invisible. Epicarp dull to glossy; monochrome; brown to black, or purple; with surface texture uniform; glabrous to glabrate, or pubescent and indurate; with hairs erect; velutinous (hairs reddish-brown); with simple hairs; eglandular; without spines; not smooth; with elevated features; veined; transversely veined relative to fruit length; not tuberculate; rugose; occasionally exfoliating in part; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp absent. Endocarp present; visible; dull; opaque; monochrome; brown to tan (grayish), or yellow to white (bright); without adhering pieces of testa; septate to subseptate (or if layered and indehiscent then part of endocarp remaining with fruit is nonseptate); not exfoliating; entire. Seed(s) 10–34; length transverse to fruit length; neither overlapping nor touching; in 1 series, or 2 or more series (2). Funiculus 1.5–12 mm long; of 1 length only, or 2 different lengths (alternately longer and shorter); filiform to thick; S-curved to contorted, or plicate. Aril absent.

Seed: 6.5–60 mm long; 3–14 mm wide; 2–13 mm thick; not overgrown; not angular; symmetrical; ovate to oblong, or elliptic to triangular (long); compressed; with surface smooth; without visible radicle and cotyledon lobes; without hilar sinus; with umbo on seed faces, or without umbo on seed faces; without medial ridge on each face. Cuticle 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 to mottled (rarely); black to brown; with tan overlay, or green overlay; glabrous; smooth, or not smooth; with elevated features; bearing endocarp remnants (occassionally); osseous. Pleurogram present; 75–100 % (P. nitida F.A.W. Miquel has both types). Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible, or fully concealed; concealed by funicular remnant; without faboid split; punctiform, or larger than punctiform; 0.2 mm long (in P. multijuga); with straight outline; linear; subapical to radicle tip to apical at apex of radicle tip (rarely); recessed; not within corona, halo, or rim. Lens not discernible. Endosperm present, or absent; thin; not pluglike and not resembling tip of radicle; adnate to testa. Cotyledons smooth; both outer faces flat; both the same thickness; both more or less of equal length; not folded; margin entire 180 degrees from base of radicle; similar at apex; completely concealing radicle; split over radicle; with lobes; with lobes overlapping; with 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; parallel to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; straight with embryonic axis; centered between cotyledons. Plumule well developed; glabrous.

Distribution

Tropical South America to Central America, Africa, and Asia to New Guinea and Fiji (Hopkins, pers. commun., 1982).

New World and Old World; West Indies to Central America to South America (tropical); Peru, Brazil, Ecuador, and the Guianas; Africa, Madagascar, India, Indochina, China, Indonesia and the Philippines, New Guinea, and Fiji (Africa and Asia to New Guinea and Fiji).
 

Generic Notes

The inflated chartaceous testa of P. bicolor remains adnate to the endocarp and not the embryo. Its embryo may fall free of the testa and fruit. Hagos (1962) noted that in the African species P. filicoidea Welwitsch ex D. Oliver the noninflated test was detached from the embryo. Hopkins (pers. commun., 1982) considered the texture of the endocarp to be an important character in this genus. The African and at best some Asian species have an endocarp consisting of a "dry farinaceous pulp" not found in mature neotropical Parkia fruits. The inner endocarp surface "of many neotropical species is smooth and white." She noted that a large quantity of amber-colored gum is produced on dehiscing by the adaxial suture of P. pendula. Similar gum also is present within indehiscent legumes of several other neotropical species, e.g., P. decussata W.A. Ducke, P. nitida F.A.W. Miquel, P. panurensis G. Bentham ex H.C. Hopkins, and P. igneiflora W.A. DUCKE.