Kimberley icons

Sunday, 12 June 2016

Yellow kapok tree, near Lady Forrest Range, Kimberley

Unsurprisingly, even when I go on holiday, I take a keen interest in the plants that surround me. A recent trip to the Kimberley region of West Australia catapulted me into seemingly a whole new world! The richly coloured, rugged scenery and the vast remoteness of the landscape were accompanied by a diversity of native flora that at first glance seemed so incredibly unlike anything I had ever seen before - yet as I got to know them better, at times I found some intriguing links to more familiar plants.

West Australia is home to some of the most magnificent of our native plants. Most of those we encountered in the Kimberley play a significant role in the culture of the local Indigenous people of the area - as a source of food, medicine or material used to make implements, and/or to signify changes in the seasons. The plants also are a vital food source for animals and birds in the region (with birds often being the pollinators for the plant), with the bold shapes and structures of the flowers in many cases reflecting this interrelationship.

Boab tree, Mornington Wildlife Sanctuary, Kimberley

Perhaps the most iconic plant of all in the region is the endearing boab tree (Adansonia gregorii). With its enormous rounded trunk beneath a spreading network of spidery branches, it is an eminently huggable tree; in a fevered flight of the imagination (after one too many glasses of champagne?) I could almost imagine them as friendly 'tree people', waddling along the endless, brilliant-red dirt roads. The boab is a deciduous tree that can get to 15 m tall, with large white or cream fragrant flowers in summer pollinated by hawkmoths and birds. For Indigenous people, the tree has many uses: for example, the large rounded fruit contains a refreshing, sherbet-tasting, edible pith, rich in vitamin C; the seeds can be consumed; the root fibres can be made into string; and young boab roots are eaten like carrots.

Bauhinia cunninghamii, El Questro Station, Kimberley

Amongst the many other trees we encountered along the way, including a variety of interesting and decorative Eucalyptus and Corymbia species, I particularly liked the Kimberley bauhinia tree (Bauhinia cunninghamii, ht 6-12 m). This is a graceful shade tree with the trademark symmetrical 'butterfly' leaflets of the genus, looking as if they have been cut from folded paper. The flowers, however, are quite different from those of the Bauhinia trees that grow in Sydney parks and gardens (this being an introduced species, most likely to be B. variegata, from India), having a conspicuous bunch of stamens in a hue of pinky-red. They bloom from May to December. The nectar of flowers is edible, and the bark and wood are used by Indigenous people for firewood, windbreaks and as medicinal ingredients. The tree often hosts native bees, providing a source of honey. An Indigenous name for the tree ('jigal') translates as 'mother-in-law tree', because of the back-to-back positioning of the leaves: according to their culture, a mother-in-law and son-in-law must not directly face one another.

Brachychiton viscidulus, Emma Gorge, El Questro Wilderness Park, Kimberley

Another fascinating tree is the Kimberley rose or sticky kurrajong (Brachychiton viscidulus). This is a relative of the native Illawarra flame tree (Brachychiton acerifolius ) that adorns Sydney gardens in late spring with its fiery red bell-shaped flowers. The Kimberley rose blooms on leafless branches from April to December, with clusters of beautiful large, pinky-red, funnel-shaped flowers, pollinated by birds. The blooms are followed by woody fruit, as with the Illawarra flame tree.

Crotalaria cunninghamii, Geikie Gorge National Park, Kimberley

A very flamboyant plant of the Kimberley region is the green bird flower (Crotalaria cunninghamii), which truly looks like a cluster of tiny birds pecking at a stem. The shrubby plant grows about 4 m tall and the blooms appear from February to November, being pollinated by bees and honeyeaters. The nectar of the flowers is a form of bush tucker.

Gossypium australe, Purnululu National Park (Bungle Bungles), Kimberley

The so-called 'native cotton' (Gossypium australe) has very attractive large pink-mauve flowers, with a deep cerise centre - reminiscent of a small hibiscus, and indeed belonging to the Malvaceae family, which includes Hibiscus, Abutilon and hollyhocks - and also the Kimberley rose! The native cotton is a shrub growing to 3 m tall and appears in a range of habitats throughout the region. Though belonging to the same genus as the plants grown as commercial cotton crop plants, it is not used for this purpose. However, there is apparently ongoing research to crossbreed desirable traits of this wild cotton species into the commercial species, such as resistance to pests and diseases, and drought tolerance.

Cochlospermum fraseri, Windjana Gorge National Park, Kimberley

Another unusual plant is the yellow kapok (Cochlospermum fraseri). This rangy shrub (or small tree, ht 6-9 m, pictured also at the start of the blog) has startlingly yellow flowers like giant buttercups, from April to September, which form large pods encasing seeds surrounded by a kapok-like down. It is not the source of kapok used for stuffing pillows (I once dismembered one of these, belonging to my grandmother, and was mesmerised by this strange yet compelling substance), which is Ceiba pentandra, an unrelated plant. For Indigenous people, however, the yellow kapok has a number of uses: the roots of the young plants are baked and eaten, and the flowers are edible. The blooming of the plant indicates when the crocodiles are laying their eggs, which can be collected for food. The tree often hosts native bees, providing a source of honey. The cottony down in the seedpods has been used for ceremonial body decoration.

Nymphaeae violaceae, Mitchell Falls, Kimberley

Some of the most haunting and unexpected sights of our trip were the beautiful waterholes and billabongs smothered with flowering native waterlilies. Such delightful vignettes were as artfully arranged as if in Monet's water garden, and looked superb against a backdrop of ghost gums that often grew at the edges of the water, providing stunning reflections. One of these waterlilies was Nymphaea violacea, with large white to bluish-purple blooms from March to December. The corms, stems and seeds of the plant are used as bush food. The corms are also used in medicine.