Darling Downs Grasslands

I recently found a really excellent blog article on the grasslands of the Darling Downs, written by a visitor from Victoria,  John Morgan, who leads the Plant Ecology Lab at the Department of Botany at La Trobe University.He speaks of "C3" and "C4" grasses.  See article below for an explanation of these terms.
My only criticism of the article is that I wish he had learned to spell the name of our fair city. (It features as "Tawoomba").
(It's an interesting perception, too, that he thinks our local botanists are "more like cowboys". One hopes this is a reference to their sensible headgear, not to their style of botany!)
See it at:
http://morganvegdynamics.blogspot.com.au/2013/03/grasslands-of-darling-downs-story-of.html

Slender Bamboo Grass, Austrostipa verticillata, a C3 grass

Grasses for All Seasons
C3 or C4?
The first grasses, like most other plants, used a type of photosynthesis known as “C3". Many of them still do. These grasses are known as winter grasses, and tend to be found in the southern half of Australia. Their seeds germinate in autumn, and the plants do most of their growing in autumn and spring. C3 grasses stay green over winter and are at their best in partially shaded areas. They flower in spring, and seeds mature in early summer, after which the plants brown off and remain dormant through the hot period. Then they return to their active growth phase in autumn.
 
River Tussock Poa labillardieri, a C3 grass


Summer  grasses were a later arrival on the evolutionary scene. They came with an innovation in photosynthesis, known as “C4", which makes particularly efficient use of atmospheric carbon dioxide. They are thought to have evolved around 30 million years ago at a time when the world temperature dropped dramatically, and the available CO2 halved. The C4 process allows these plants to photosynthesise while keeping the pores in their leaves closed. This saves water, but works best in hot conditions. Their ability to make efficient use of water means that they make more green leaf out of a given amount of water than C3 grasses do.

Queensland Blue Grass (Silky Blue Grass) Dichanthium sericeum, a C4 grass.
C4 grasses evolved in the tropics, and their descendants are still happiest in the northern parts of Australia, where the rains come in summer. Their  seeds germinate best in hot, wet weather. Typically fast-growing plants, they are more active in summer than winter, and they prefer to grow in full sun.
Once established, (as indicated by their first flowering), they are very drought hardy. After growing and flowering actively throughout the summer, they have a little rest period in winter, and may brown off.
C4 grasses also tend to be well-adapted to poorer soil..

 Barb wire grass Cymbopogon refractus, a C4 grass
We live in the part of Australia where C3 and C4 grasses overlap. Those of us who like to grow grasses in our gardens have plenty of local native species of both types to choose from. This is a great convenience for gardening, because a mixture allows us to have actively growing green grass for most of the year.
It also means that we can have the beauty of their flowers and seedheads – and the bird-attracting seeds – for a longer period than we would if we only grew one kind or the other.


Choosing Local Grasses for Local Gardens
Here is a shortlist of the more popular perennial grasses for garden use:

C3 Grasses
Austrodanthonia bipartita (Rytidosperma bipartitum) LEAFY WALLABY GRASS
Austrodanthonia racemosa (Rytidosperma racemosum) CLUSTERED WALLABY GRASS
Austrodanthonia tenuior (Rytidosperma tenuius) PURPLISH WALLABY GRASS
Austrostipa aristiglumis PLUMP SPEARGRASS (PLAINS GRASS)
Austrostipa ramosissima STOUT BAMBOO GRASS
Austrostipa verticillata SLENDER BAMBOO GRASS
Elymus scaber WHEAT GRASS
Microlaena stipoides WEEPING RICE-GRASS
Notodanthonia longifolia (Rytidosperma longifolium) LONG-LEAF WALLABY GRASS
Poa labillardieri RIVER TUSSOCK
Poa sieberiana SNOW GRASS

C4 Grasses
Bothriochloa bladhii FOREST BLUEGRASS
Bothriochloa erianthoides (Sorghum erianthoides) SATIN TOP
Capillipedium spicigerum SCENTED TOP
Chloris truncata WINDMILL GRASS
Chloris ventricosa TALL WINDMILL GRASS
Cymbopogon refractus BARB WIRE GRASS
Dichanthium sericium QUEENSLAND BLUE GRASS
Dichanthium queenslandicum KING BLUEGRASS  NB: listed as VULNERABLE
Panicum decompositum NATIVE MILLET
Panicum queenslandicum,  YABILA GRASS (Umbrella grass)
Sarga leiocladum (Sorghum leiocladum) NATIVE SORGHUM
Themeda avenacea NATIVE OAT GRASS
Themeda triandra  (Themeda australis) KANGAROO GRASS

Kangaroo Grass Themeda Triandra

Soft Water Vine

Cayratia eurynema
Family: VITACEAE
Climbing is one of plants’ knackiest inventions.
Leaves are their little solar power stations, and the more of them it can place in sunny positions, the better the plant grows. You know the story, I’m sure. Using solar energy, leaves convert carbon (from carbon dioxide in the air), and hydrogen (from water, which is made of hydrogen and oxygen) into carbohydrates. They release lots of lovely oxygen in the process, and use the carbohydrates for body-building and the energy to do it.

In a crowded environment with a dense canopy, new little plants may never be able reach enough light. Many wither on the forest floor.
Rainforests are called “vine forests” for a good reason, though. All sorts of quite unrelated plants have evolved into vines. Climbing has given them the ability to acquire height quickly. Because they use other plants for support, they don’t have to spend time and energy building their own trunks. Therefore they can compete effectively for a share of the sunlight, at a much earlier age than a seedling tree, germinated at the same time, could ever do.
They use a lot of different techniques. Some just scramble, poking lots of little branchlets among the foliage of other plants to support themselves. Some use thorns to hang on. Some twine their stems around any support they can find - I have even seen a blood vine twining up a strong strand of the web of a golden orb spider.
Some have developed specialised twining organs, called tendrils.
All those methods depend the climber finding suitable bits of vegetation to grab.






Just a few plants have bypassed all that, and climb straight up the trunks of giant trees. Most of them do it with clinging roots, produced along their stems.















Cayratias, like a very few other members of the grape family, have a very specialised way of achieving it. They have adhesive discs on the ends of their tendrils.

Some of their overseas relatives like Boston ivy Parthenocissus tricuspidata (which is really a kind of grape, not an ivy at all) and Virginia creeper (P. quinquefolia) have found a special place in gardens because of this ability. They can climb on masonry, so are used to ornament brick walls and buildings.
Our local soft water vine can probably be used in the same way. Plants with clinging tendrils have the advantage over root-climbers like ivy, in that they restrict themselves to the wall’s surface, rather than sending questing roots into mortar and tiny cracks, to grow and break the wall apart.
The soft water vine can also be grown on trellises and pergolas.
It is an attractive foliage plant, one of the few local examples of plants with "pedately compound" leaves. Note how the stem first divides into three, then two of these divisions divide into two. This distinctive style of leaf makes it easy to identify in its native rainforest habitat.
 
 Soft water vine has large bunches of tiny white flowers, and bird-attracting little black “grapes”.
It is frost tender, and can tolerate heavy shade (which means it can also be used indoors, as a pot plant).

White Bollygum

Neolitsea dealbata
Family: LAURACEAE
I took this photo last week in Goomburra National Park.

You can see that this tree has fruits in the bird-attracting colours of red and black. They are ripening progressively, which , besides making the tree highly attractive, will provide food for an extended period. White-headed pigeons were there in a crowd.
We can find the plant growing naturally along Great Dividing Range, mostly on the eastern side, but also in damper, more sheltered western sites within a few kilometres of the Range. It differs from its rainforest cousin Neolitsea australe in having larger leaves, smaller and more colourful fruits (about 1cm) and a bit of hairiness in the shoots, leaf-stems, and the veins on the backs of the leaves. Mature leaves have white backs, and are aromatic when crushed. Note the brown, hairy leaf-stem (petiole).

Extremely good value in a garden, it is a fast-growing small tree. It makes an excellent screen with foliage extending to the ground, or can be trimmed up to make a small shade tree. Drought hardier than other Neolitseas, it is a suitable candidate for waterwise gardens in Toowoomba and nearby red soil areas. Like all dry rainforest plants, however, it grows faster if watered and mulched in its first few years of life.
It would prefer a frost-free corner of the garden.
New flushes of leaves are very ornamental. A soft shade of pinkish brown, they hang limply all over the plant.

This young plant is growing in a local garden. Photographed last November, its new flush of leaves were just hardening off.



 
White bollygum is a member of the laurel family, whose members are all host plants for blue triangle butterflies.

Smooth Water Vine

Cayratia saponaria
Family: VITACEAE
There are five different local species of Cayratia, all known as water vines, or sometimes “native grapes”. They are in the grape family, which is obvious if you look at their recognisably “grapey”seeds. Fruits of smooth water vine have just two very large seeds per fruit. These fruits are edible, but said to be not particularly tasty. They can irritate the lining of the throat if eaten in quantity. I’m kicking myself, though, that I wasted this opportunity to try some. It is always risky to put an unknown fruit in your mouth, but I had already checked it for the typical grape seeds, so knew it would be safe.


Smooth water vine is rarely seen here nowadays, but probably once grew in the long-gone rainforests of the Toowoomba City precinct. It can still be found in the rainforest on the southern slope of Mount Tabletop.
It can grow into a large vine, with a stem diameter eventually reaching 10cm. It would make an attractive pergola plant, needing a sheltered site when young, and probably always growing best if it has a cool, well-mulched root-run.
The stems are high in saponins. It is said to be possible to make a good soapy lather in water, suitable for washing clothes and hair, by cutting them into foot-long lengths and heating them till they’re soft .

Smooth water vine has its name from its shiny green leaves. These distinguish it from the very similar “hairy water vine” Cayratia saponaria, which often shares the habitat with its cousin and has softly velvety leaves.
Cayratias grow well in full shade, and make lovely foliage plants for indoor use.

Some of the Best Bush Tucker

Capparis sarmentosa
Family: CAPPARACEAE
All our native caper species have edible fruit, but these take out the prize for flavour.


They are full of black seeds embedded in sweet flesh. The seeds can be swallowed, as with passionfruit, or spat out according to your personal preference.



The plant they grow on is called scrambling caper, and is a prickly little vine which clings to tree trunks in its native dry rainforest habitat. It is rather slow-growing at first In a garden it would be best planted close to the trunk of a tree, where the interesting geometry of its network of tiny, fine-leafed stems can be best appreciated. It could also be led up a wooden fence or shaded masonry wall, where it would certainly help keep a property secure from intruders!

You would probably choose to train it away from garden pathways, though, as it does tend to snatch and grab at passers-by, with its tiny pairs of kitten-claws.



The  capers used in cooking are not fruits at all. They are pickled flower-buds, from Capparis spinosa, a shrub native to the Mediterranean region. No doubt buds of this species could be used in the same way - but it seems a pity not to leave the plants for their pretty spring flowers and the fruits that follow.
As with most Capparis, the young plants have smaller leaves than the mature ones shown above.
They are very pretty, and cling securely to their supports.

 A correspondent has described these young plants as "green lace".

Like all our native capers, this species is guaranteed to attract native butterflies, whose caterpillars live on the leaves.

Capparis sarmentosa is a drought hardy plant, with a preference for growing in partial shade

Holly-leafed Bird’s Eye

Alectryon subdentatus
Family: SAPINDACEAEAutumn in Australia is marked, not by a conspicuous display of autumn leaf colour, but by fruits on the native trees.
It the case of dry rainforest trees, these can be showy things, as with these birds eye fruits I photographed in Peacehaven Botanic Park yesterday.

“Alectryon” means rooster, and you can see from the fruit, why the tree was given this name.
Most Alectryon species are neat little shade trees. As a botanic garden, Peacehaven is intended to show how suitable our local native plants can be for use in gardens, and this is a good example of a plant suitable for quite small gardens.
Red and black are bird-attracting colours, so you can see how appealing the generous crop of fruit on this tree would be. The red aril can also be eaten by humans, and I have read claims that it tastes quite acceptable. I find it dry, astringent and disgusting, and suspect that wishful thinking rather than experience is behind the claims.
Hard bird’s eye seems to be the Alectryon which fruits at the earliest age. This tree is about seven years old.
Its red new leaves can appear at any time of year, when the tree puts on a spurt of growth after rain. They are usually at their best in spring, though. They make the plant attractive from a very early age.

A walk around Peacehaven is rewarding at the moment, with many of the small trees flowering or fruiting. Notice that the fruits of the holly-leafed bird's eye tend to be double. In the photo below, they are being split open by the aril, which swells as it ripens.

Near this tree in Peacehaven is a specimen of grey bird’s eye, Alectryon connatus (with ashy-grey leaf-backs). Its seed capsules are triple or quadruple. A number of Alectryon species have some triple capsules, but this is the only one to have the quadruple ones. For this reason, it is sometimes called “quad Alectryon”. 

The Snap, Crackle, Pop Tree

Excoecaria dallachyana
Family: EUPHORBIACEAE
A friend rang me last week to say that her exploding tree was doing it again! She had been out feeding the chooks, and the tree, about 20 metres away, had attracted her attention with its noise. Would I like to come over and hear it?
Well, how could I resist?
The tree was one of the original dry rainforest trees on her property, and was making the kind of noise that could teach Rice Bubbles a thing or two! Its tiny seed capsules were bursting open and releasing their seeds at a rate which made it look as though it was spitting with rain under the tree.


Even photographing them was not straightforward, as some of the little three-cornered capsules on my hand burst as I was holding them in the sun, spitting their three seeds away and knocking the other capsules about.
The tree snapped and crackled for at least three hours that day, and to judge by the quantity of seed it still had, is probably still doing it whenever the weather is warm and dry enough.
The seeds developed from inconspicuous winter flowers like these.

Note the plant’s tendency to have fresh green leaves on old-looking twigs. This helps to identify it in the wild. It grows as a shrub or small tree, usually to 4 or 5 metres, though it can apparently reach 15 metres in rainforest.



This plant isn’t often seen in gardens. Its common names include scrub poison tree, and blind-your-eye. Hardly good press, for what is a very attractive tree with a shiny green canopy. I usually see it in the scrub, where its shape is affected by other close-growing plants. The only garden-grown specimen I’ve seen was a particularly beautiful, well-shaped young tree with dense foliage to the ground.







Its bad reputation comes from its white sap. I doesn’t trouble the skin on my hands, but I wouldn’t risk it on my lips or eyes. There is a story that it troubled timbergetters in the old days, as chopping it with axes caused the sap to squirt about a bit, including into their eyes, resulting in blindness for several days.

I don’t think this plant would be any more dangerous in the garden than plants like frangipani, poinsettia and euphorbia, and common weeds like milkweed (often recommended for growing as a butterfly host) and the weedy little spurges that can be found in every garden. Like them, it would need to be handled with care if being cut or pruned. Putting a potentially harmful plant into a garden is something that should never be done without careful consideration.