Taccarum Brongn. ex Schott

CATE Araceae, 17 Dec 2011. araceae.e-monocot.org

General Description

HABIT : seasonally dormant herbs, often robust, tuber depressed-globose. LEAF : solitary. PETIOLE : terete, mottled and variegated or not, sheath very short. BLADE : juvenile leaves simply lobed, adult leaves trifid to trisect, anterior division usually deeply bipinnatifid, often tripinnatifid in lower pinnae, posterior divisions deeply pedatifid with segments themselves pinnatifid, ultimate lobes subtriangular to elliptic or lanceolate, acute to acuminate, broadly decurrent; basal ribs well-developed, primary lateral veins of ultimate lobes pinnate, running into inconspicuous marginal vein, higher order venation reticulate. INFLORESCENCE : 1, rarely 2 in each floral sympodium. PEDUNCLE : usually much shorter than petiole. SPATHE : not constricted, tube convolute, blade gaping to widely spreading, marcescent and later deciduous ( T. weddellianu m). SPADIX : free or female zone adnate to spathe, sessile or stipitate, erect, much longer than, subequal to or shorter than spathe, male zone usually contiguous with female, rarely with a few bisexual flowers in between, fertile to apex. FLOWERS : unisexual, perigone absent. MALE FLOWER : 3-8-androus, stamens connate, synandrium very long-stipitate with apical whorl of anthers to short with anthers near base, stigmatoid apex inconspicuous or distinct and 4-6-lobed, or very large and dome-shaped, thecae oblong or broadly ellipsoid, dehiscing by short apical slit or pore. POLLEN : extruded in strands, inaperturate, ellipsoid to oblong, large (mean 63 µm., range 49-76 µm.), exine scabrate or verruculate or spinulose-spinose, or smooth (psilate). FEMALE FLOWER : gynoecium surrounded by whorl of 4-6 free, erect, filiform, clavate or oblong, often flattened staminodes, or by urceolate synandrode composed of connate staminodes ( T. caudatum), ovary 3-6(-7)-locular, ovules 1 per locule, anatropous, funicle short, placenta axile, style very long and slender or very short to ± absent, always narrower than ovary, stigma thick, capitate or 5-7-lobed, lobes erect or stellate. BERRY : borne in cylindric infructescence, depressed-globose, slightly furrowed, style persistent, 3-5-seeded, . SEED : ellipsoid, raphe conspicuous, testa granulate, light brown, embryo straight, elongate, endosperm copious.

Habitat

Open tropical woodland ( cerrado), forests, humid mountain valleys; geophytes, often in stony soils or between rocks.

Distribution

S. Trop. America to N. Argentina.

Diagnostic

Often robust, seasonally dormant, tuberous geophytes; leaf solitary; leaf blade dracontioid, ultimate lobes lacking submarginal collective veins, fine venation reticulate; spadix fertile to apex, male and female zones usually contiguous; flowers unisexual, perigone absent; male flower a stipitate synandrium; female flower with a whorl of free or connate staminodes. Differs from Asterostigma in having leaf blades subdracontioid to dracontioid, synandria elongate, stigma capitate or with rounded lobes (lobes star- or cross-like in Asterostigma).