Which of the following is a flowering plant with nodules containing filamentous nitrogen-fixing micro-organism?

Nitrogen-fixing organisms are found associated with Casuarina equisetifolia. It harbours a $\mathrm{N}_2$-fixing organism Frankia in their roots in the form of nodules. Related Theory Casuarina equisetifolia is also known as Austratian pine, ironwood, beefwood, she oak and horsetail tree, which is a deciduous tree with a soft, wispy, pinelike appearance that can grow to 100 feet or more in height. It bears a superficial resemblance to the conifer. genus Pinus because of its small, round, cone like fruits and its branchlets of scale-like leaves that look like pine needles.