Adaptations to dry climate include scale-light verticillate leaves, waxy leaves and modified needle-like twigs for reducing transpiration by means of sunken stomata lying in grooves, hairs, thickened cells and cuticle. Roots have nodules with symbiotic nitrogen fixing bacteria. It is salt tolerant, enables it to adapted to growth on sand dunes and also as lower branches root and upright branches develop. Reproductive Structures
C. equisetifolia male flowers growing at the tip of the needle-like leaves The species is monoecious or dioecious with 2-3% of the individuals being monoecious. Male flowers have a cat-tail shape while the female flowers are hard, cone-like. A wind pollinated. The fruit is like a woody cone, 1 to 2 cm in diameter and will change colour from green to deep-brown when it reaches maturity. They contain 70-90 seeds and take 3-4 months to mature. The seeds (achenes: 600 to 2000 seeds per g) have a membranous wing and are wind-dispersed. They can also be water-dispersed. Nature Environment
Casuarina trees lining the beach
Row of female flowers and a young fruit
A light demanding species which needs open sites for establishment, free from plant competition. It forms permanent stands in saline coastal environments and sand dunes due to the needle-like structure that act as a windbreak and its high salt tolerant. Climate
Var. equisetifolia occurs in the hot humid and sub-humid zone (monsoonal). Typical rainfall lies between 1000 and 1500 mm a year.