Swartzia xanthopetala Sandwith
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Authority
Cowan, Richard S. 1967. Swartzia (Leguminosae, Caesalpinioideae Swartzieae). Fl. Neotrop. Monogr. 1: 3-228. (Published by NYBG Press)
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Family
Fabaceae
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Scientific Name
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Type
Type collection. N. T. Sandwith 388 (holotype K; isotypes F, G, LE, NY, RB, S, U, US, W), Moraballi Creek, Essequibo R., Guyana, Oct. 1929.
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Description
Description - Tree 22 m tall, the trunk 1.5 dm diameter, the branchlets dark-brown velutinous; stipules caducous, 4 mm long, 2.5-3 mm wide, ovate, acute, velutinous externally, strigulose basally within; petioles terete, bluntly stipellate at the apex, 2-5 cm long, dark-brown velutinous, the rachis 7-10 cm long, canaliculate, stipellate at each pair of leaflets, dark-brown velutinous; leaflets (l-)3- (or 4-) jugate, the petiolules 2-4 mm long, velutinous, the blades of the lowermost pair smaller and oval to oblong-oval, 4.5-9 cm long, 3-4.5 cm wide, the remaining blades elliptic to elliptic-oblong, 8.5-14 cm long, 3.5-6 cm wide, the base and apex of all the leaflets rounded-obtuse, sometimes the apex apiculate, more or less tomentose on both sides, the venation conspicuous, impressed on the upper surface, salient beneath; inflorescence racemose, ramigerous, 5-20 cm long, the axis tomentose-velutinous, the bracts persistent, 2-4 mm long, 3-3.5 mm wide, ovate, velutinous externally, strigulose in the basal half within, the bracteoles persistent, arising at the apex of the pedicels, 2-3 mm long, 0.5-1 mm wide, oblong, acute, velutinous externally; pedicels 12-22 mm long, velutinous; buds subglobose, ca 10 mm long, 9 mm diameter, velutinous; calyx segments 4, thick, coriaceous, velutinous externally, glabrous within; petal bright yellow, the claw 3-3.5 mm long, the blade 25-30 mm long and wide, oblate-ovate, cordate, villose-sericeous externally, especially on the veins, glabrous within; large stamens 13-18, glabrous, the filaments ca 20 mm long, the anthers oblong narrowly, 2 mm long, 0.7 mm wide, the smaller stamens glabrous, the filaments 8-12 mm long, the anthers oval, 1 mm long; gynoecium glabrous, the stigma truncate-capitellate, the style 5-8 mm long, the ovary 17.5-25 mm long, 1-1.75 mm wide, arcuate-linear, the stipe 7-9.5 mm long; fruit not seen.
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Discussion
Sandwith was quite correct in suggesting considerable affinity between S. picta and S. xanthopetala, but an even closer relationship appears to exist with S. leiogyne, which has differently shaped leaflets and a marginate to narrowly alate leaf rachis. S. picta can be distinguished also by its sinuate-dentate petal and its leaflets being glaucous beneath.
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Distribution
(Fig. 5). Only the type collection has been seen and this was gathered in the wallaba [Eperua] forest on a ridge in the near interior of Guyana. Sandwith cites Jenman 4505 from the “Demerara River,” but I have not seen a sheet of this collection.
Guyana South America|