Bocoa

Taxonomy

Bocoa J.B.C.F. Aublet Hist. Pl. Guiane Suppl. 38. t. 391. Jun 1775.

Subfamily: Faboideae.
Phylogenetic Number: 3.1.02.
Tribe: Swartzieae.
Group: Swartzia.
Species Studied - Species in Genus: 6 studied; 7 in genus.

Description

Fruit: A legume; unilocular; 0.8–3 cm long; 0.8–2.5 cm wide; 0.8–2 cm thick; 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; not plicate; not twisted; asymmetrical; obliquely elliptic, or ovate, or circular, or rhombic; with both sutures parallelly curved, or both sutures unequally curved; not inflated; terete, or compressed; without beak, or with beak (1–2 mm long); straight; with solid beak the same color and texture as fruit; short tapered at apex, or rounded at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; short tapered at base; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; substipitate, or nonstipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down; passive. Replum invisible. Epicarp dull; monochrome; reddish to greenish brown, or tan; with surface texture uniform; glabrous to pubescent and indurate; with hairs erect; with 1 type of pubescence; rarely puberulent; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; with elevated features; usually veined; reticulately veined; not tuberculate; scaly tessellate; 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 balsamic vesicles; without fibers; without reniform canals; solid; coriaceous. Endocarp present; visible; dull; opaque; monochrome; reddish brown, or tan; smooth; without adhering pieces of testa; septate, or nonseptate; with septa thin (tissue paper-like), flexible; with septa eglandular; coriaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 1; length parallel with fruit length. Funiculus 1.5–3(–3000) mm long (in B. prouacensis J.B.C.F. Aublet 1.5–3 m long (Cowan 1974)); filiform; straight. Aril absent, or present (in B. prouacensis J.B.C.F. Aublet and B. viridiflora (W.A. Ducke) R.S. Cowan); fleshy; laciniate; covering less than 1/2 of seed; white.

Seed: 8–27 mm long; 3.5–13 mm wide; 2.7–13 mm thick; not overgrown; not angular; asymmetrical; oblong, or ovate; 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; without pieces of adhering epicarp; not adhering to endocarp, or partially adhering to endocarp; free from endocarp; dull, or glossy; not modified by a bloom; colored; monochrome; yellowish brown, or tan, or black; glabrous; smooth, or not smooth; with elevated features; wrinkled; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible; without faboid split; punctiform; subapical to radicle tip; flush; not within corona, halo, or rim. Lens not discernible. Endosperm absent. 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; entire over radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; reddish brown; inner face flat; glabrous on inner face. Embryonic axis oblique, or parallel; oblique to length of seed, or parallel to length of seed; with a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; triangular; deflexed and parallel to cotyledon width; centered between cotyledons; less than 1/2 length of cotyledons (much less). Plumule rudimentary; glabrous.

Distribution

Eastern Peru, Eastern coastal and Amazonian Brazil, Guyana, and French Guiana.

New World; South America (Peru (eastern), Brazil (east coast and Amazonian), Guyana, French Guiana); Peru, Brazil, Ecuador, and the Guianas.
 

Generic Notes

Cowan (1974) revised Bocoa. Herendeen (1994), in his cladistic analyses of Swartzieae genera, split Bocoa into two species groups "to reduce character polymorphism": 1) those species with opposite leaflets, colpus membrane coarse granular, and arillate seeds and 2) those with alternate leaflets, colpus membrane fine granular, and nonarillate seeds. In unweighted cladistic analyses, the first group was in a clade with Swartzia (1.01) and Candolleodendron (1.03), and the second was at the base of a clade consisting of Baphiopsis (1.05) and six Sophoreae (2) genera. In weighted cladistic analyses, both Bocoa groups were part of the clade including Swartzia and Candolleodendron. The cotyledonary and embryonic structures of Bocoa are similar to those of Baphiopsis and different from those of Swartzia, suggesting that Bocoa belongs to the clade with Baphiopsis and the six Sophoreae genera. Cowan (1974) reported that the funiculus of B. prouacensis J.B.C.F. Aublet is 1.5–3 m long and suggested that this, in combination with its aril, is part of a dispersal syndrome with animals.

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.