Those Mysterious Leaf-glands

We are all aware, (at least I think we are), that plants produce nectar in their flowers to attract pollinators. These are usually insects, though some plant species use birds or other animals.
The glands which produce it are called nectaries. They are surrounded by a beautifully engineered arrangement of petals, designed to ensure that only those capable of carrying pollen to other flowers can reach the nectar - and then only if they align themselves just as the flower requires. (Flowers are bossier than you'd think!)
This means that the pollinator body-part, which gets dusted with pollen in one flower, will then be correctly positioned to deliver it to the appropriate bit of the next one. It has to be deposited on the stigma, to do the job of fertilising the flower’s future seeds.
Somewhat less known, however, is that plants have other nectaries which are open to all comers. They are called “extra-floral” nectaries - “extra” as in Latin for “outside”.

They can be on various parts of the plant, but a common position is at the base of the leaf. Croton species provide a good example, with their little glands visible to the naked eye (provided it has good eyesight, or has its specs on). Here they are on Croton phebalioides...

 ...and here on Croton insularis.








Such an easily accessible source of highly nutritious nectar could be found by all sorts of tiny creatures, but a common result is that the fiercest will discover it and keep it for themselves,  chasing away (or eating) potential rivals. In this way, the plant attracts protectors, usually ants, which help to keep it safe from other little sap-sucking, leaf-biting creatures.
Isn't that just so knacky?

Toowoomba’s Oldest Tree?

Ficus rubiginosa  (Ficus obliqua var. petiolaris)
Family: MORACEAE
Toowoomba botanist John Swarbrick has drawn my attention to this magnificent tree. It is a “Scrub Fig”, and can be found in Meredith Crescent.  

 This part of Toowoomba was once part of the garden of Carl Hartmann (1833 - 1887), a noted Toowoomba botanist, explorer and nurseryman who is now best known for his involvement in the establishment of our city’s original Botanic Gardens in Lindsay Street.
Hartmann cultivated 22 of his 40 acres, creating a magnificent garden of his own which contained plants from all over the world. It became a favourite destination for Toowoomba’s weekend picnickers. There was even a bus service which brought people from town for their pleasant day out. Some of the specimens he planted can still be found in the streets and private gardens in that part of Toowoomba.

The fig is an unusually large one of its kind, so it’s more than likely that it was a mature plant at the time Hartmann cleared the land. Much change has happened around it, including a lowering of the soil level. The tree still stands on a mound which would have been the original height of the ground.

Growing in the tree are several large, old blood vines Austrosteenisia blackii. Which probably also pre-date European settlement of the area.

Most of their little leaves are up in the canopy, mixed with the larger leaves of the fig.












However the odd few sprout lower down, and have enabled us to identify the vine, which still grows naturally in Redwood Park, and may have once been common in the Toowoomba City area itself.

Blood vines produce large panicles of deep red flowers in late spring. They would be a sight worth seeing, on such a large vine as this one. We must keep an eye out for them!
Meanwhile, the tree is producing a large crop of figs, which will provide a feast for our native birds.

Which Nettle?

Urtica urens, Urtica incisa
Family: URTICACEAE



Until recently, I believed that the only nettle found in the Toowoomba area was this plant, the native perennial Urtica incisa. It's a plant which can die back to its roots in winter, but regrows again in spring.
I was aware that the annual nettle Urtica urens had been introduced to Australia, but didn’t think it had found its way into this district.







Obviously I spend too much time in the bush, and not enough time in Toowoomba gardens!
I was shown Urtica urens in a West Street garden the other day.

It had made itself well and truly at home in a piece of fallow vegetable garden.  It’s just as well that such a rampant plant has a practical use, as a very good  green manure!
The garden’s owner was quite happy about having nettles, though, as she uses them in her herbal tea.
Both nettles have somewhat variable leaves, but the native Urtica incisa can be easily distinguished from the introduced plant by its flower heads. Note that in the upper photo, which shows the native nettle,  the stem on which the flowers grow is unbranched and as long as, or longer than, the leaf-stem. By contrast the flowers on the introduced nettle, (lower photo) are on much shorter stems and tend to branch.
( A double click on the photo lets you enlarge it, to see the details.)
For some of the many uses of nettles, see my blog of October 2008.

Five-fingered Jack

Adiantum hispidulum
Family: ADIANTACEAE

This little fern is looking splendid in my garden at present.
It’s a native maidenhair, more drought-hardy than the more familiar common maidenhair (which is also native), therefore a good garden plant. It likes to have all its leaves cut off once a year. I did it to this plant in autumn, and you can see how beautifully it has bounced back.
Its favourite site is a position where it gets some full sun, but for less than half a day. Mine is against a west-facing wall.

          Poor Jack, by the way, is not good at counting. He might actually have as many as eight fingers.

Long Yam

Dioscorea transversa
Family: DIOSCOREACEAE

Before the days of white settlement,the roots of this yam were one of the staple foods of the people in this district. The first white settlers knew the area we now call Prince Henry Heights as “the Yam Ridge”, because this plant was abundant in the rainforest there.

Uneven ground said to be the remains of Aboriginal diggings for the plant can still be seen beside the path in Ravensbourne National Park.

Long yam’s fragrant pale green flowers are beginning to appear now in our local rainforests, and they will be followed (on the female plants) by 3-lobed capsules which will mature to purplish brown, then fade to straw colour and a papery texture as they ripen.

Though we often notice the leaves in the wild, we may have difficulty tracing the plants back to their sources. The inconspicuous, slender stems ramble through shrubs and understorey plants, putting out leaves wherever a patch of sunlight creates the right conditions.

If the point can be found where they exit the ground, some digging reveals a bunch of white carrot-shaped tubers not much thicker than a pencil. They are edible raw, (when small), and said to be delicious roasted. 
Now do they, or do they not, look yummy to you?

The plants die back to their tubers in dry winters.

This is a very drought hardy plant that is ideal to let naturalise in a shrubbery or rainforest-style garden. It is attractive as a foliage specimen, but we must remember to put in a number of plants if we want the pretty seed capsules. Male and female plants are needed for this!

They make charming container plants, looking their best if several are put in a single pot and a small structure provided for climbing.

Shade-lovers, they can be used indoors or out.

Birds Nest Bush

Pittosporum viscidum (Citriobatus linearis)

I couldn’t resist taking a photo of this plant, living up to its name. I crouched to take the picture, so as to show the nest clearly, but the result gives a poor impression of the size of the plant.
It is really not much higher than I am, with a puff of prickly foliage about 50cm diameter - quite large enough, however, to provide a perfect site for this little nest!

Grown in full sun, it forms a dense canopy to ground level. Trimmed or untrimmed, it is a plant which could be used for a hedgerow in the traditional English hawthorn style, sheltering wildlife as it makes a thorny barrier.

  It has sweetly-scented flowers in October, followed by yellow fruits which ripen to black.

 
Crushed between the fingers, the ripe fruits yield a fine, citrus-scented oil that makes an effective hand lotion.

This plant is very hardy to both drought and frost.

Yellow Elderberry

Sambucus australasica
Family: SAMBUCACEAE
This plant is growing in a delightful rainforest-style garden in Toowoomba . Its situation there resembles its natural habitat, where it is a slender shrub whose bright green leaves are not particularly conspicuous among the general greenery. Only when it produces these pretty translucent berries does it attract attention. Unlike so many plants, it is capable of flowering and fruiting in heavy shade.

The famous Australian botanist, Joseph Maiden, wrote in 1889: “the fruit of (this plant) is fleshy and sweetish, and is used by the aborigines for food”. Having tried it myself, I found that its flavour is best described as “tolerable”.  I would prefer to leave it for the birds!

The plant is said to tolerate light frosts.