Thursday, November 25, 2010

Canary Muskheart

Alangium villosum

When it comes to domatia, this tree is an enthusiast!

Many plant species have these little pits along their mid-veins, but I’ve never before come across leaves so generously endowed with them.
Domatia are an ingenious plant invention. As their name implies, they are little “homes” provided by plants for the accommodation of mites. Most of the mites which make themselves at home there are beneficial ones. They protect the leaf by eating tiny herbivorous insects, fungi and other disease pathogens.
Unfortunately for the landlord, some undesirable tenants are also likely to move in - but the overall balance is usually one where beneficial mites dominate, so the overall effect for the plant, of providing this free mite accommodation, is a protective one - and you can see how healthy this leaf is looking.
Canary muskheart gets its common name from its bright yellow sapwood, and the dense, dark, musk-scented heartwood inside it. It once occurred naturally in Toowoomba, but is now only found in the Boyce Garden, where it grows naturally in the last remnant of our original rainforest.
Old specimens of canary muskheart can reach 20m high and to a diameter of 90cm. Large trees are seldom seen, however. Early timbergetters probably cut it with enthusiasm, as its timber is outstandingly beautiful. Close-grained and firm, it is valued by conoisseurs of fine woods for carving and turnery. It was also popular for walking sticks, so even small trees were cut.
Its little yellow flowers are honeysuckle scented, and the succulent black fruits are the size and shape of olives, but have longitudinal ribbing. They are a favourite fruit of rainforest pigeons.
This is a plant which likes to grow on a variety of soils, including basalt redsoil, and prefers to be sheltered and partially shaded when young. It is slow-growing, and may never reach its full potential size in a suburban garden. However, slow-growing plants should be a part of every garden which is not to vanish without trace in the future.

Sweet Morinda

Gynochthodes jasminoides (Morinda jasminoides)
Like the plant above, this vine’s domatia are also “over the top”.

In this case, it’s not their numbers which impress, but their size. The mite-habitat pits are so large that they make conspicuous bumps on the upperside of the leaves, making the plant easy to identify when it's not flowering or fruiting.
“Morinda” is an Indian word, and is the common name for Morinda citrifolia, a plant which grows in south-east Asia, some Pacific islands, and in tropical northern Australia. It is also called Indian mulberry or noni fruit. Its potato-sized fruit tastes foul, and may be toxic if too much is consumed, but is nonetheless popular for its alleged health-giving properties. The bark and leaves of the Indian Mulberry yield a red dye, while yellow dye is made from its roots. As with its relative the mulberry, its leaves can be used to raise silkworms. Our local Morindas may be found to have some of the same useful qualities, but like many Australian plants, their potential has never been fully explored.
Our two local Morinda species typically grow on the edges of both moist and dry rain forests, and in vine thickets. Sweet morinda is the larger of the two.
In the open, it grows into a large tangled shrub - great for covering an ugly tree-stump or hiding a tumbledown shed. With a bit of discipline from the secateurs, it makes a handsome bird-sheltering shrub. If there is anything to climb on, however, this plant will do it with enthusiasm. Despite its somewhat disorderly behaviour, it’s one of our prettiest native plants. Even when not flowering or fruiting, its very shiny leaves make it appealing.

Sweet Morinda is named for the scent of its creamy, butterfly-attracting white flowers, which are produced for up to three months in spring and early summer. They are followed by lumpy, orange, bird-attracting orange fruits, up to 2cm in diameter. These are worth a close look, being actually compound fruits formed by the fusion of many tiny fruits, with no two quite alike.

Saturday, November 13, 2010

The Cutest Dragon

Darling Downs Earless Dragon (Tympanocryptis pinguicolla)

This little fellow was on display yesterday in a Pittsworth Landcare display at Bunnings in Toowoomba.

It is classified as Endangered in Queensland (Nature Conservation Act 1992) and nationally (Environment Protection and Biodiversity Conservation Act 1999). These acts classify flora and fauna as”not of concern”, “threatened”, “vulnerable”, “endangered”, and “extinct” - in that order.
One of Australia’s smallest dragon-lizards, it is only 12cm long including its rather long tail. It’s not really earless. The ears are just hidden behind scales.
The lizards’ natural habitat is the treeless grassland which grows on the cracking black clay soils of the Darling Downs. (A separate population of a very similar lizard, which may or may not turn out to be the same species, is found in southern New South Wales, Victoria, and the ACT.)
The lizards come out in the daytime to look for the little insects which they eat - but they can be hard to find, because of their tendency to disappear down the cracks in the blacksoil. This year they’ve been a bit easier to see, as the good rains have closed the cracks. They have also made the grass grow, however (see article on Plains Grass below) - so the lizards can find have plenty of places to hide, in the gaps between tall tussocks. And they do need to be able to hide, as cats and foxes are very effective enemies.
It is breeding season, so males in breeding colour (bright yellow throat and chin) and pregnant females are about.
One of the most endangered environments in our area is the grassland, which once made the Darling Downs so famous. It persisted for a century after white settlement, when grazing was a major industry on the Downs, but has disappeared rapidly since the 1950s, as the grazing industry has moved west, replaced here by croplands. There are a few small protected areas, but no dragons have been found in any of them. Grasslands with a potential to be dragon habitat do still occur on roadsides, but are very prone to mismanagement from an environmental point of view. So the dragons are, at present, quite dependant on private landowners for their existence. They have been shown to be able to survive in intensely cropped areas, but must also appreciate the shelter provided in preserved remnants of grassland such as the one described below.

Friday, November 12, 2010

Thready-leafed Hopbush

Dodonaea sinuolata
Toowoomba Field Naturalists were privileged to be able to visit the new McEwan State Forest, out near Pittsworth, last weekend. Not yet open to the public, this newly acquired land is expected to become a national park - something we badly need in this area - and to be open to the public in the next year or so.

One of the plants we saw there was this very pretty hop-bush.

Like the other hop-bushes, it flowers inconspicuously, then produces its showy seed capsules in spring each year.
It may be our prettiest local hop-bush, with its frilly-winged pink capsules. Though grown as an ornamental in America, it can be difficult to purchase here in its own country, though I notice it’s available from the Greening Australia nursery in Brisbane. One would need to buy several seedlings to ensure getting hops, as they occur only on the female plants. They could be grown in groups, to make dense clumps. They can be expected to grow to about head-height - but may make a prettier (denser) plant if kept lower by pruning.
There are about 70 species of Dodonaea. Most of them are Australian, but some are found in other tropical or sub-tropical countries - Africa, Asia, and America. They are related to the introduced Koelreuteria (Golden Rain) trees which are used as street trees in toowoomba, and put on such a lovely show every autumn, with their coppery seed capsules. Unlike the Koelreuteria, hop bushes are not environmental weeds!
The name “hop-bush” was given to them by early settlers, who apparently used their seed capsules as substitutes for the completely unrelated true hops (Humulus lupulus) in brewing beer. I have no idea whether they were actually any good for the purpose!

Plains Grass

Austrostipa aristiglumis
We don't often see native grasslands these days. This one is composed largely of Plains Grass, which was once a dominant grassland type on the Darling Downs. It is on private property near Mt Tyson.
Although this is potentially very good grazing land, the ungrazed paddock has been retained by the farm's owners because of its value as habitat for wildlife - particularly the rare grassland earless dragon (Tympanocryptis pinguicolla).
I imagine there are other reptiles which would also like living here - which made me feel quite cautious about tramping into this situation!

Preservation of the grassland will provide habitat for numerous other wildlife species, including mammals and birds, which appreciate the feast of plump seeds on these pretty heads.
Seed of plains grass (also called "plump speargrass") is available commercially, as it is also appreciated by landscape gardeners. A patch of them, besides being attractive, would add value to any wildlife-friendly garden - particularly one on black soil. A densely planted stand will exclude most weeds.

Plains grass self-seeds readily. Its interesting seeds are “self-planting” having awns (the little whiskers on their ends) which twist more or less according to the humidity, and, with a little help from the wind, make the seeds burrow into the ground. However it is unlikely ever to become a weedy nuisance, as it is shallow-rooted and easy to uproot by hand. It is also killed by lawnmowing, so can easily be confined to a designated garden plot.
This is a drought and frost hardy plant, which prefers to grow in full sun.

Saturday, November 6, 2010

Red Passionflower

Passiflora aurantia

I found this little vine in flower at Picnic Point, this week (on the walking trail that runs alongside the road.)

It’s a dainty little tendril-climbing plant, with these showy flowers that are white when they first open, but mature, over four days, through pink to red.

Related to commercial passionfruit, they have the same characteristics in the flowers which led Spanish missionaries in America to give passionflowers their name - they saw them as symbols of the passion of Christ.

Look carefully and you can see the crown of thorns in the flower (the red bit on the white flower), the ten “petals” representing the ten faithful disciples, the three pistils symbolising the nails, and the five anthers Christ’s wounds - and so on.
The flowers drip with sweet nectar, so attract honeyeaters and insects.
The fruits, which will develop after these flowers die, are about 3cm long, and ripen from green to purple. Like all passionfruits, they are poisonous when unripe, but can be eaten once they’ve turned purple (though the flavour is not interesting).
As with so many rainforest climbers, they like to have their roots well-shaded and mulched, but want their heads in the sun for part of the day, for good flowering.
They could be grown on a small trellis, either in the ground or as a pot plant. Alternatively, their tendrils are said to be so effective that they can climb brick walls, so perhaps they could be used to add a decorative note to a boring wall (though I imagine they would object to the heat of the afternoon sun). They would certainly be inoffensive light climbers for the purpose, unlikely to damage brickwork or reach higher than 2 metres.
The plants are fast-growing but not long-lived. For a good display of flowers, it would be best to grow a number of the plants, with new ones inserted amongst the old every now and again.
The seed may germinate more readily if fermented first, but as the plant is easily reproduced from cuttings you may decide this is the way to go.
The plant is the local native host for glasswing butterflies - one of our less showy species, but interesting, with their transparent wings. This little butterfly is more common nowadays than it ever was, despite the decline in numbers of its native host plant. Glasswings can also breed on Passiflora foetida - otherwise known as Love-in-the-mist - or for the more prosaic of you, “stinky passionflower”.

This introduced weed is one of those plants which is probably here to stay in the Australian environment. It’s a vigorous plant which can out-compete our gentle local red passionflowers, so you need not feel guilty about picking caterpillars off the local plant species. They need protection more than the caterpillars do.