Antopetitia

Taxonomy

Antopetitia A. Richard Ann. Sci. Nat. Bot. ser. 2. 14: 261. Nov 1840.

Subfamily: Faboideae.
Phylogenetic Number: 3.13.16.
Tribe: Loteae.
Species Studied - Species in Genus: 1 studied; 1 in genus.

Description

Fruit: A legume, or a loment (or a loment segment) (not a true loment); unilocular; 0.7–1.2 cm long; 0.2–0.25 cm wide; 0.23 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with persistent calyx; with calyx shorter than fruit; without orifice formed by curving of fruit or fruit segments; slightly curved to curved; not plicate; not twisted; asymmetrical; falcate, or moniliform; with both sutures parallelly curved; not inflated; terete; with beak (small); straight; with solid beak the same color and texture as fruit; rounded at apex; aligned with longitudinal axis of fruit; short tapered at base; oblique with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous; seed chambers externally visible; seed chambers with the raised seed chambers not torulose; margin constricted; margin constricted along both margins; margin without sulcus; margin plain; wing(s) absent; substipitate (may be longer than 2–3 mm if lowest locule aborted); with all layers dehiscing; fenestrating, opening by a coiling strip of tissue. Dehiscence of valves along 1 suture; passive. Replum invisible. Loment dehiscing along 1 suture; segments (articles) inconspicuous; segments (articles) 2–2.5 mm long; segments (articles) widest across seed area; segments (articles) with apical 1 different shape than middle one(s), or basal 1 different shape than middle one(s); segments (articles) circular. Epicarp glossy; monochrome; light brown to tan; with surface texture uniform; glabrous; eglandular; without spines; not smooth; with elevated features; veined; reticulately veined; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; surface not veined; 1-layered; without fibers; without reniform canals; solid; coriaceous. Endocarp present; visible; glossy; opaque; monochrome; tan, or white; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 2–4; length parallel with fruit length; neither overlapping nor touching; in 2 or more series. Funiculus of 1 length only; thick; straight. Aril absent.

Seed: 1.5–2 mm long; 1.2–1.7 mm wide; 0.5–1.3 mm thick; not overgrown; angular to not angular; asymmetrical; circular to irregular; compressed; 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; dull; not modified by a bloom; colored; monochrome; dark to reddish brown to tan (reddish); glabrous; not smooth; with elevated features; rugose, or tuberculate; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible; without faboid split (hilum too small); punctiform; between cotyledon and radicle lobe; flush; not within corona, halo, or rim. Lens not discernible. Endosperm present; thick; not pluglike and not resembling tip of radicle; covering entire embryo; 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; not concealing radicle; entire over radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; yellow; inner face flat; glabrous on inner face. Embryonic axis deflexed; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose; oblique to cotyledons; centered between cotyledons; 1/2 to nearly length of cotyledons. Plumule rudimentary; glabrous.

Distribution

Tropical Africa.

Old World; Africa (tropical).

Generic Notes

Polhill (1981l) noted that this genus is closely related to Ornithopus (13.15), and that the genera of the Coronilleae only differ from those of the Loteae (13) by the presence of jointed fruits in the former. Verdcourt (1974) noted that Antopetitia is "a monotypic genus closely allied to Ornithopus L., but differing in the pod segments being dehiscent and in the persistent dorsal suture." Both authors alluded to an anomaly in fruit of Antopetita. These fruits are unique in the Fabaceae. At first glance they appear to be loments, but they are not. At most they are loment-like or lomentaceous, because the fruits dehisce albeit by a unique mechanism. In addition, Léonard (1954: figure 10) clearly illustrated that the fruit dehisces on the plant: The seeds falling free of the fruiting cluster. By definition a loment separates at maturity into 1-seeded indehiscent articles. The unique dehiscence mechanism is the opening of the valves by the rolling up of the vertical suture. In so doing the individual fruit segments become fenstrated and then the seed may fall out or one valve may fall off (Léonard, 1954: figure 10). Upon soaking the testa fractures because of the rapidly expanding endosperm as it does in Scorpiurus (13.14). Both the seed and fruit dehiscences are related to edaphic factors in the habitat of the species.

Tribal Notes

Tribe Loteae

In 1981, Polhill (1981k) accepted much broader generic circumscriptions in tribe Loteae, and only accepted four genera in the tribe: Cytisopsis, Anthyllis (13.02), Hymenocarpus (13.04), and Lotus (13.07). In his most recent classification of Fabaceae (Polhill, 1994a, 1994b), he combined tribes Loteae and Coronilleae and accepted six segregate genera in Loteae, s.s.: Tripodion (13.03), Dorycnopsis (13.05), Dorycnium (13.06), Podolotus J.F. Royle (13.08), Pseudolotus K.H. Rechinger (13.09), and Vermifrux (13.10).