Gleditsia

Taxonomy

Gleditsia C. Linnaeus Sp. Pl. 1056. 1 Mai 1753.

Subfamily: Caesalpinioideae.
Phylogenetic Number: 1.1.02.
Tribe: Caesalpinieae.
Group: Gleditsia.
Species Studied - Species in Genus: 12 studied; ca. 14 in genus.

Description

Fruit: A legume; unilocular; 2–45 cm long; 1.5–8 cm wide; 0.2–1.2 cm thick; length less than twice as long as width to 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; twisted, or not twisted; symmetrical, or asymmetrical; linear to lanceolate, or ovate, or elliptic to oblanceolate, or falcate; with both sutures parallelly curved; not inflated; flattened to compressed; without beak; long tapered at apex; aligned with longitudinal axis of fruit; tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous to ligneous, or membranous (when fresh); seed chambers externally invisible, or visible; margin constricted, or not constricted; margin slightly constricted only on 1 margin; margin without sulcus; margin plain; wing(s) absent; stipitate to substipitate; with the stipe 6–20 mm long; tardily with all layers dehiscing to indehiscent; splitting along suture(s). Dehiscence of valves passive. Replum invisible. Epicarp dull and glaucous; monochrome; brown to black (reddish); with surface texture uniform; glabrous, or pubescent and indurate; with hairs erect; eglandular; without spines; not smooth; with elevated features; veined; transversely veined relative to fruit length; not tuberculate; exfoliating to not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present, or absent; surface not veined; 1-layered, or 2-layered; without balsamic vesicles; without fibers; without reniform canals; solid; with spongy layer over solid layer; ligneous to coriaceous. Endocarp present; visible; dull; opaque; monochrome; tan; without adhering pieces of testa; subseptate to nonseptate; not exfoliating; remaining fused to mesocarp and epicarp; entire. Seed(s) 1–40; length transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.01–25 mm long; of 1 length only; filiform to thick; plicate. Aril absent.

Seed: 8–17 mm long; 5–10.5 mm wide; 2–6 mm thick; not overgrown; angular, or not angular; symmetrical; ovate, or elliptic, or rectangular, or quadrangular, or circular; terete to compressed; 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 to dull; not modified by a bloom; colored; monochrome; brown (greenish to blackish); glabrous; smooth; osseous. Pleurogram absent. Pseudopleurogram absent. Fracture lines present; concentric. Rim absent. Wing(s) absent. Raphe not visible ("inconspicuous"). Hilum present; fully concealed; concealed by funicular remnant; without faboid split; punctiform; apical at apex of radicle tip, or subapical to radicle tip; flush; not within corona, halo, or rim. Lens discernible; 0.1–10 mm long; with margins straight, or curved; wedge-shaped; circular; not in groove of raphe; flush to recessed; same color as testa to dissimilar color from testa; black, or tan (center); not within corona, halo, or rim. Endosperm present; thick; not pluglike and not resembling tip of radicle; adnate to testa. Cotyledons smooth; both outer faces convex; both the same thickness; both more or less of equal length; not folded; margin entire 180 degrees from base of radicle; similar at apex; partially concealing radicle; with lobes; with lobes touching (auriculate), or 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; parallel to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; centered between cotyledons. Plumule moderately developed; glabrous.

Distribution

Eastern North America, Southern South America, around the Vaspian sea, India to Japan and Philippine Islands.

New World and Old World; eastern United States and South America (southern); Argentina and Brazil; Russia, Southwest Asia, India, Indochina, China, Korea, Japan, and Indonesia and the Philippines (around Caspian Sea and Philippine Islands).
 

Generic Notes

Gordon (1966) monographed Gleditsia. The gummy mesocarp, present in all but three species, is edible. The fruits of G. triacanthos L. have been described as 'anachronistic' because they supposedly evolved for dispersal by Pleistocene megafauna that are now extinct (Barlow 2000).