Swartzia

Taxonomy

Swartzia J.C.D. von Schreber Nom. cons. Gen. 518. Mai 1791.

Subfamily: Faboideae.
Phylogenetic Number: 3.1.01.
Tribe: Swartzieae.
Group: Swartzia.
Species Studied - Species in Genus: 55 studied; ca. 133 in genus.

Description

Fruit: A legume; unilocular; 2–34 cm long; 1–9 cm wide; 1–2.5 cm thick; 2–9 times longer than wide, or length less than twice as long as width; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight, or curved (slightly); not plicate; not twisted; symmetrical, or asymmetrical; oblong, or elliptic, or ovate, or circular, or moniliform; with 1 straight and 1 curved suture, or both sutures parallelly curved, or both sutures nearly straight; widest near middle or D-shaped; not inflated, or inflated; terete, or compressed; without beak, or with beak; straight; with solid beak the same color and texture as fruit; short tapered at apex, or rounded at apex, or tapered at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit, or right-angled with longitudinal axis of fruit; short tapered at base, or rounded at base; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit, or right angled with longitudinal axis of fruit; with the apex and base uniform in texture; ligneous, or leathery, or fleshy; seed chambers externally invisible, or visible; seed chambers with the raised seed chambers not torulose; margin not constricted, or constricted; margin constricted along both margins; margin without sulcus, or with sulcus; margin plain; wing(s) absent; stipitate, or substipitate; with the stipe 0.1–30 mm long; with all layers dehiscing, or indehiscent (especially fleshy fruit); splitting along suture(s). Dehiscence of valves along both sutures, or 1 suture; apical and down; passive, or active; with valves enrolling. Replum invisible. Epicarp dull; monochrome, or multicolored; mottled, or bichrome (because of tan lenticels); brown (various shades and combinations with other colors), or black, or yellow, or orange; with black overlay, or tan overlay (lenticels); with surface texture uniform; glabrous, or pubescent and indurate; with hairs erect; with 1 type of pubescence; puberulent, or tomentose (minutely), or sericeous, or peltate (densely micropuberulent); with pubescence gray, or red; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; smooth, or not smooth; with elevated features; not veined, or veined; reticulately veined; not tuberculate; wrinkled (to reticulate), or verrucose-rugose, or ribbed, or rugose, or shagreen, or tessellate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thick; surface not veined; 1-layered, or 2-layered; without balsamic vesicles; without fibers; without reniform canals; solid, or firm-walled open empty cells; with vitriol layer over solid layer; ligneous. Endocarp present; visible; dull; opaque; monochrome, or mottled; tan; with mottling more or less uniform (dark); with purple overlay; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 1–12; length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.1–40 mm long (longer ones dangle seeds from dehisced fruits); of 1 length only; flattened, or filiform; straight, or contorted. Aril present, or absent; fleshy; when fleshy marginal hilar, or caplike, or flat from apex to near base, or marginal around seed, or leaflike and attached to marginal hilum; fimbriate; covering less than 1/2 of seed, or 1/2 to nearly all of seed; white, or cream, or red.

Seed: 2–70 mm long; 2–60 mm wide; 8.5–18 mm thick; overgrown, 1 seed filling entire fruit cavity, or not overgrown; not angular, or angular; asymmetrical; C-shaped, or irregular, or ovate, or quadrangular, or reniform, or rhombic, or circular; terete, or 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 (often not firmly surrounding embryo); without pieces of adhering epicarp; not adhering to endocarp; free from endocarp; glossy, or dull; not modified by a bloom; colored; monochrome, or mottled; with frequent mottles (white mottles over brown in S. panamensis); brown to pale, grayish brown, or cream, or gray, or olive, or black; with brown overlay (dark); glabrous; not smooth, or smooth; with elevated features, or recessed features; wrinkled; pitted with small separate pits; chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe visible, or not visible; from hilum to near base of seed and terminating (or going 1/2 way around seed); not bifurcating; lighter than testa; tan; flush. Hilum present; fully concealed, or visible; concealed by aril; without faboid split; larger than punctiform, or punctiform; 0.1–20 mm long; with curved outline, or straight outline, or angular outline (more or less); circular; wedge-shaped; oblong (and some up to 3/4 diameter of seed), or linear (and some up to 3/4 diameter of seed); marginal according to radicle tip, or subapical to radicle tip; recessed; not within corona, halo, or rim, or within halo; halo lighter than testa. Lens not discernible. Endosperm absent. Cotyledons smooth, or not smooth; rugose, or wrinkled; both outer faces convex, or outer face of one cotyledon flat and other cotyledon convex; both the same thickness, or one thicker than the other; both more or less of equal length, or 1 longer than other; not folded, or with both folded; sufficiently folded for inner face to touch itself, or not sufficiently folded for inner face to touch itself; portions of inner folded face unequal; margin entire 180 degrees from base of radicle; similar at apex; partially concealing radicle, or completely concealing radicle (if radicle differentiated); entire over radicle; without lobes; with the interface division terminating at base of radicle, or in radicle tissue; without margins recessed; dark reddish to dark greenish brown, or green (dark brownish); inner face flat, or concave (at least 1 cotyledon); glabrous on inner face. Embryonic axis parallel; parallel to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon, or not differentiated from cotyledon; triangular (when developed); lobe tip straight; straight with embryonic axis; centered between cotyledons, or not centered between cotyledons (radicle outside 1 cotyledon and inside other, therefore junctions for each cotyledon different); less than 1/2 length of cotyledons (much less). Plumule rudimentary; glabrous.

Distribution

Neotropics.

New World; West Indies to Mexico to Central America to South America; Peru, Brazil, Ecuador, and the Guianas.

Generic Notes

The New World species of Swartzia were monographed by Cowan (1968). Kooposhian (1963) noted that most external and internal seed characters are faboidlike. The caesalpinioid seed feature is the simple hilum with a single epidermis layer and no tracheid bar. Corner (1951) noted that a "bony ridge" is visible simulating the tracheid bar in the subhilum. Based on seed and fruit characters, Swartzia was a heterogeneous genus. Clearly S. madagascariensis A.N. Desvaux and S. fistuloides H.A.T. Harms (both African) belong in the subfamily Faboideae. The key character is the presence of a faboid split in the hilum coupled with the presence of a raphe, lens, and bent embryonic axis. Swartzia madagascarensis and S. fistuloides were so clearly not members of the genus Swartzia that they were transferred to the new genus Bobgunnia (1.01A) which was established as a result of this study (Kirkbride and Wiersema, 1997). Even omitting these species from Swartzia and unlike most other faboid genera, it is impossible to represent Swartzia with one internal seed drawing. Some seeds of Swartzia discolored the dissection fluid.

Tribal Notes

Tribe Swartzieae

Swartzieae has been assigned to Caesalpinioideae (Cowan, 1968), Swartzioideae (de Candolle, 1825a, 1825b; Corner, 1976), and Faboideae (Bentham, 1865, Hutchinson, 1964, Cowan, 1981). In 1968, Cowan (1968) was unable "finally to resolve the sub-familial relationship of Swartzia," but in 1981, he (Cowan 1981) placed it in the Faboideae and stated, "... features appear to support the arrangement adopted here (Cowan 1981) with the Swartzieae representing a relatively less-advanced position in the Papilionoideae (Faboideae). This conclusion is now supported by wood anatomy ..., by nodulation proclivity ..., and by chemistry ...; chromosome numbers of n=8, 10 or 14 ..., as well as pollen morphology ..., do not negate this conclusion." In the most recent assessment of the Fabaceae, Polhill (1994a, 1994b) maintained Swartzieae as a basal tribe of Faboideae, "transitional to the Caesalpinioideae." He transferred four genera from Sophoreae (2) into the Swartzieae, Amburana (3.1.15), Ateleia (3.1.13), Cyathostegia (3.1.14), and Holocalyx (3.1.12), and arranged the genera in four groups corresponding to clades in Herendeen's (1994) cladistic analysis. Herendeen carried out cladistic analyses using morphological characters of all Swartzieae genera, 19 genera of Sophoreae, and three Caesalpinioideae genera. He concluded that Swartzieae is polyphyletic and that it should be disbanded and its genera transferred to Sophoreae. Preliminary rbcL data (Doyle et al. 1997) supported his conclusions. Ireland et al. (2000) also carried out molecular phylogenetic studies. They also concluded that Swartizeae is polyphyletic, and suggested that possibly tribe Swartzieae could be maintained with Swartzia (3.1.01), Bobgunnia (3.1.01A), Bocoa (3.1.02), Ateleia (3.1.13), Cyathostegia (3.1.14) and the current remaining Swartzieae genera transferred to other tribes. Our seed data neither support nor refute the overall outlines of Herendeen's cladograms; they are discussed below for a few genera. Ferguson and Skvarla (1991) reported on the pollen morphology of Aldina and Swartzia (1.01), and the nine other genera of Swartzieae are covered in Ferguson and Skvarla (1988). Their data are summarized in a computer-generated key in Vezey et al. (1991). The pollen data for the tribe should be compared with our seed-fruit morphological data.