Mildbraediodendron

Taxonomy

Mildbraediodendron H.A.T. Harms In Mildbraed, Deutsche Zentral-Afrika Exped. 1907–8 2: 241. 1911.

Subfamily: Faboideae.
Phylogenetic Number: 3.1.07.
Tribe: Swartzieae.
Group: Aldina.
Species Studied - Species in Genus: 1 studied; 1 in genus.

Description

Fruit: A legume; unilocular; 10 cm long; 10 cm wide; 10 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; symmetrical; circular; not inflated; terete; without beak; rounded at apex; aligned with longitudinal axis of fruit; rounded at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; leathery, or coriaceous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; stipitate; with the stipe 5–6 mm long; indehiscent. Replum invisible. Epicarp dull; monochrome; with surface texture uniform; without spines; not tuberculate; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present. Seed(s) 1–5; length transverse to fruit length; touching, or neither overlapping nor touching; in 1 series. Aril absent.

Seed: 55 mm long; 35 mm wide; 15 mm thick; not overgrown; not angular; symmetrical; oblong; compressed; with surface smooth; without visible radicle and cotyledon lobes; without hilar sinus; without umbo on seed faces; without medial ridge on each face. Testa absent. Endosperm absent. Cotyledons not smooth; 4–6 grooves on each face; 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; completely concealing radicle; split over radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; tan; 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; linear; lobe tip straight; straight with embryonic axis; centered between cotyledons; less than 1/2 length of cotyledons. Plumule well developed; glabrous.

Distribution

Tropical Africa.

Old World; Africa (tropical).

Generic Notes

We had no fruits available for study. Aubréville (1970) has a sketch of the fruit in his figure 74. See Cordyla (1.06) for discussion of Herendeen's cladistic analyses.

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.