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Araceae
Xanthosoma latestigmatum Bogner & E.G.Gonç.
Nomenclature
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Family: AraceaeGenus: Xanthosoma
SUMMARY
Herb with a dormant stage, with a tuber (2-)3-4 cm in diameter. Leaves several, basal, tufted, pilose in all parts; petiole 25-32 cm long and 0.2-0.4 cm in diameter, maculate, pilose (rough with very short stiff hairs); sheath 6-8 cm long; leaf blade pedatisect, leaflets (in adult stage) (7-)11-13, mid to light green (not shiny), lower face covered with very short whitish hairs, densely so on the veins, upper face also with very short whitish hairs and slightly rough-textured; rachis 7-10 cm long and 0.1-0.3 cm in diameter, distance between leaflets 0.5-2 cm, becoming shorter towards outermost leaflets; leaflets oblanceolate to elliptic or sometimes elliptic-oblong, the central one the largest, 5-10(-12) cm long and (1.5-)2-4 cm wide, the lateral smaller up to 5-10(-12) cm long and 0.5-1.5 cm wide, the outermost often only 1-2 cm long; apex cuspidate, base cuneate, sessile (on rachis), in the lateral leaflets decurrent on one side onto the rachis; venation reticulate; midrib well differentiated, primary lateral veins 6-10 on each side, interprimary veins present between them, third order veins much more slender; inner collective vein 1-2 mm distant from margin, outer collective vein ± 0.5 mm distant from margin. Cataphylls 8-9 cm long, membranaceous. Peduncle 10-15 cm long and 0.4-0.5(-0.8) cm in diameter, finely maculate, pilose (covered with very short dense hairs). Spathe 10-16 cm long, constricted at the middle, outside pilose, inside glabrous; tube somewhat inflated, convolute, 5-6 cm long and 2-2.5 cm in diameter, light green; limb ovate-oblong, 5-9 cm long, white to greenish white with red margin, apex cuspidate. Spadix shorter than spathe, 9-12 cm long, shortly stipitate; female zone ± cylindric to obconic, 1.5-2 cm long and 0.7-1.2 cm in diameter; sterile zone (between female and male zone) 1.5-2.5 cm long, basally much thicker and 1.2-1.5 cm in diameter with large synandrodes, apically 0.5-0.8 cm in diameter, white, synandrodes elliptic to oblong when viewed from above, the flattened surface with somewhat sunken centre, 6-7 mm long and 3-4 mm wide, c. 2 mm deep, the lowermost thickly swollen and c. 4 mm deep; male zone fertile to apex, whitish to cream-coloured, 5-8 cm long, basally c. 8 mm in diameter and narrowing towards acute apex. Flowers unisexual, naked. Female flowers (gynoecia), densely arranged c. 3 mm long and 1.2-1.3 mm in diameter, ovary somewhat ovoid, c. 2 mm long and 1-1.2 mm in diameter, white, with 2-3(-4) deeply intrusive placentae, ovules many, hemianatropous, c. 0.2 mm long; style broad, 0.8 mm thick and approximately as broad as the ovary, coherent, whitish to pale yellow, stigma disc-like, somewhat sunken centrally, yellow, 0.8-1 mm in diameter, papillose. Male flowers (synandria) connate of 5-6 anthers (10-12 thecae), whitish to cream coloured, flat-topped, sometimes somewhat irregular, well incised by the anthers (viewed from above), c. 2 mm deep, the lower ones elliptic when viewed from above, 2-3.5 mm long and 1.8-2.2 mm wide, then becoming broader and ± roundish towards middle of the male zone, 2-3 mm in diameter, the uppermost smaller, 1.8-2 mm in diameter with c. 4 anthers (= 8 thecae), thecae situated laterally and long-cylindric, c. 1.8 mm long, slender, c. 0.25 mm in diameter, opening by an apical pore. Pollen released in monads, grains globular, inaperturate, c. 30 μm in diameter, exine psilate.