Swamp She-Oak Forest & Kim Starr/Flickr

Swamp She-Oak

Casuarina glauca

Did You Know?

  • Also called a casuarina because their branchlets look very similar to a cassowary feather
FactBox Image

Evergreen tree, greyish-brown bark has oak-like appearance, branchlets spreading or drooping. Can be found solo or in dense stands.

Usually 8 – 15 m high. Can reach a maximum of 20 m high (rarely) and only reaches 2 m high on clifftops. The trunk can be up to 35 cm in diameter. This tree is also found in prostrate form (lying flat on the ground), reaching 30 cm high and 2 m wide.

Leaves

Segmented branchlets with very small teeth-like leaves (0.6 - 0.9 mm long), 12 – 17 leaves arise at the nodes of segments. New growth is strongly recurved (bent or curved backwards or downwards) and become erect as they mature.

Flowers

This species is dioecious (male and female reproductive structures develop on different individuals). Male inflorescences (arrangement of flowers) are spikes, growing 1.2 – long with 7 - 10 whorls per cm (ring of floral parts borne at the same level) and a 0.8 mm long anther (pollen-bearing part of the stamen).

Fruits/Seeds

Cylindric, ovular cones are 9 - 18 mm long and 7 - 9 mm in diameter are found on a 3 - 12 mm long stalks. Cones range from rust-coloured to white; they are pubescent (covered with short, soft, erect hairs).

Samaras (dry fruit with wings that do not open) are 3.5 – 6mm long (including the wings).

Species: WhatToObserve Image

What to Observe

  • First fully open single flower

  • Full flowering (record all days)

  • End of flowering (when 95% of the flowers have faded)

  • No flowering

  • Fruiting

  • Seed pods present/absent

Species: WhenAndWhere Image

When and Where

When To Look

  • Peak in branchlet fall in summer, less in winter
  • Mass flowering of male flowers in August and September
  • Female flowers less obvious, occurring in small numbers throughout spring
  • Young fruit can be seen in summer and reaches maturity by autumn
  • Fruit falls more commonly in the winter months
  • Cones mature in winter, causing prolific seed fall

Where To Look

  • All states except Tasmania
  • In or near brackish waterways
  • Planted for soil stabilisation along creeks, rivers and estuaries
Species: WhatElse Image

What Else?

The She-Oak doesn’t have big leaves, instead they have branchlets with different segments. They do have miniature leaves that you can see when you snap a branchlet on one of its joins.