Tontelea
Description
Lianas, slender shrubs or small trees, essentially glabrous; branches opposite or subopposite, often swollen and slightly flattened at the nodes. Leaves often with intermediates between the secondary veins. Inflorescences axillary on leafy or defoliate branches, thyrsoid-paniculate or(pseudo-)dichotomously branched; flowers loosely clustered, 2-5 together at or near the end of ultimate branchlets, subtended by minute, caducous bracts. Sepals 5 (rarely 4 or 6), entire to fimbriate; petals 5 (rarely 4 or 6), usually rounded, often papillose distally; disk short tubular, margin entire, undulate or crenulate; stamens 3, erect to reflexed, filaments ligulate, sometimes broadened towards the base, anthers transversely ellipsoid or reniform, dehiscing by transverse, confluent clefts either apical or extrorsely, and then giving a butterfly-like appearance (not so in T. cylindrocarpa and T. nectandrifolia); ovary depressed-conical or subtrigonous, 3-locular, ovules 2-4 per locule (to 8 in T. cylindrocarpa), collateral or superposed, style short, subulate or truncate (then stigmas obsolete), stigmas 3, conspicuously divaricate, opposite to or alternating with the stamens, entire, emarginate, bilobed or bifid. Fruits usually subglobose, ellipsoid or cylindric, pericarp coriaceous to woody; seeds usually few, angled, embedded in mucilaginous pulp.
Distribution
Guianas present present, Neotropics present, Peruvian and Bolivian Amazon present, Southern America: Brazil South (Paraná present); Honduras (Honduras present); Paraguay (Paraguay present)
31 species in the Neotropics from Honduras to the Guianas, Peruvian and Bolivian Amazon, Brazil south to Parana and Paraguay; 8 species in the Guianas.
Wood observation species
Wood
Growth rings absent or faint.
Vessels diffuse, exclusively solitary, or with a few clusters of 2-3, seldom with radial multiples of 2-5, 11-20 per sq. mm, often with slightly irregular distribution, round or oval, diameter usually of two sizes, small ones 30-60 μm wide and larger ones 80-100(-150) μm wide. Vessel-member length: 590-650 μm. Perforations simple. Inter- vascular pits difficult to observe, small, 2-5 μm, the slits sometimes confluent, elliptic. Vessel-ray pits similar.
Rays either all uniseriate (T. attenuata,T. nectandrifolia ), or uni- and biseriate (T. cylindrocarpa , T. mauritioides ), in T. cylindrocarpa also aggregate rays present, 12-18 per mm. Heterogeneous with numerous tall upright cells and cells grading to square, procumbent cells very rare, from 2-18 cells (= 1200 μm) high. Rhombic crystals rather numerous.
Parenchyma scarce, paratracheal as incomplete vasicentric rings, apotracheal as isolated strands, or absent, difficult to distinguish from the septate fibres. Strands of 8 cells new time.
Ground tissue of fibre-tracheids and septate fibres. Fibre-tracheids lumen 8-12 μm, walls 2.5-6 μm, small bordered pits numerous on both radial and tangential walls. Septate fibres with a lumen of 12-16 μm, walls 1-2.3 μm, in parenchyma-like distribution. In 2-3 cells wide concentric bands inT. attenuata and in T. mauritioides , in the other species aliform-confluent, cells often filled with resin, pits simple. Length offibre-tracheids: 1040(930-1200) μm. F/V ratio: 1.54-1.59. Included phloem present in all species except in the young stem of T. attenuata . In T. cylindrocarpa as isolated, roundish phloem islands, 400-700 μm wide, arranged in concentric rings and isolated from each other by wide aggregate rays often containing nests of stone cells. In T. mauritioides concentric rings without interconnections, in the other species concentric rings with radial or oblique interconnections of conjunctive tissue of parenchyma and sclerotic cells.
Vessels diffuse, exclusively solitary, or with a few clusters of 2-3, seldom with radial multiples of 2-5, 11-20 per sq. mm, often with slightly irregular distribution, round or oval, diameter usually of two sizes, small ones 30-60 μm wide and larger ones 80-100(-150) μm wide. Vessel-member length: 590-650 μm. Perforations simple. Inter- vascular pits difficult to observe, small, 2-5 μm, the slits sometimes confluent, elliptic. Vessel-ray pits similar.
Rays either all uniseriate (T. attenuata,
Parenchyma scarce, paratracheal as incomplete vasicentric rings, apotracheal as isolated strands, or absent, difficult to distinguish from the septate fibres. Strands of 8 cells new time.
Ground tissue of fibre-tracheids and septate fibres. Fibre-tracheids lumen 8-12 μm, walls 2.5-6 μm, small bordered pits numerous on both radial and tangential walls. Septate fibres with a lumen of 12-16 μm, walls 1-2.3 μm, in parenchyma-like distribution. In 2-3 cells wide concentric bands in