Casuarina
Content
Description
Trees or shrubs, monoecious or dioecious. Leaves in whorls, scale-like, connate, forming dentate sheaths. Inflorescences unisexual, catkin-like, the staminate ones elongate, the pistillate ones (sub)capitate. Flowers without perianth, subtended by bractlets; stamen 1; pistil 1, ovary unilocular, ovules 2, stigmas 2. Fruits one-seeded samaras, each enclosed by enlarged, more or less woody bractlets, aggregated into a cone-like infructescence.
Wood
Growth rings faint to absent. Vessels diffuse to slightly in radial or diagonal pattern, almost exclusively solitary, round to oval, 10-13 per sq. mm, diameter 80-100 (30-140) μm. White deposits sometimes present. Vessel-member length: 410-530 (230-760) μm. Perforations mostly simple but scalariform perforations with 3-12 bars present in narrow vessels (less than 5% of the vessels). Intervascular pits opposite to alternate, round to oval, with slit-like, often crossed apertures, 3-7 μm in horizontal diameter. Pits between vessels and tracheids in single vertical rows to alternate. Vessel-ray pits round (4 μm) to rarely vertically elongated (10 μm), alternate to opposite, half-bordered. Vessel-parenchyma pits uncommon.
Rays 1-2-3-seriate, 10-12 per mm, 210-270 μm high, homoge-neous. Crystals in chambered procumbent cells sometimes observed.
Parenchyma in regular to irregular narrow bands, predominantly apotracheal, but often also touching the vessels, scanty and diffuse-in- aggregate. Strands of 6-10 cells. Chambered crystals often in the strands in contact with the rays (2-16 per strand).
Ground tissue composed of tracheids (around the vessels) intergrading with fibre-tracheids. Pits distinctly bordered, 3-5 μm, common in radial and tangential walls. Length: 900-1100 (640-1420) μm. F/V ratio: 2.1-2.3.
Rays 1-2-3-seriate, 10-12 per mm, 210-270 μm high, homoge-neous. Crystals in chambered procumbent cells sometimes observed.
Parenchyma in regular to irregular narrow bands, predominantly apotracheal, but often also touching the vessels, scanty and diffuse-in- aggregate. Strands of 6-10 cells. Chambered crystals often in the strands in contact with the rays (2-16 per strand).
Ground tissue composed of tracheids (around the vessels) intergrading with fibre-tracheids. Pits distinctly bordered, 3-5 μm, common in radial and tangential walls. Length: 900-1100 (640-1420) μm. F/V ratio: 2.1-2.3.