Butterfly Season

What a wonderful butterfly season we are having this year.
I suppose you have all noticed that this is a big year for caper whites (Belenois java teutonia)?
This is the butterfly with the fairly plain wingtops, white with black edging,


and the beautifully marked underside which you only notice if you look a little more carefully, or see one at rest.

I don’t think anyone knows quite why they sometimes have a spectacular year like this. We haven’t had one since before the 2011 floods, so perhaps they do better when the weather is dry.
People speak of them “migrating”, which suggests a purposeful journey with a planned end in mind. What they are really doing seems to be more of a random radiation. Perhaps they have exhausted their local host plants and are simply flying away in hope of finding more. They turn up in great numbers in the southern states where the host plants don’t occur naturally. There manage to find the few cultivated specimens, where they can be seen flying in a whirling mass around the plant. The males and females fly in separate migrations, but obviously succeed in meeting up, as they have been seen laying eggs in Victoria. (If they can’t find a caper plant, they lay on unsuitable plants, and the caterpillars die.)
They also fly out over the Pacific Ocean in their many thousands. Odd specimens have been known to turn up as far away as Samoa.
The butterflies breed on our local native caper plants, Capparis arborea, C. mitchellii, C. lasiantha and C. sarmentosa. Like most local butterfly host plants, gardeners rarely plant them, so the butterflies breed in the country and can only be enjoyed in our towns because they are strong flyers who will often drop in for a refreshing sip of nectar in our gardens. (Butterflies with less strong flying skills and migratory urges are disappearing from our urban areas, as they just can’t make the flight from the increasingly distant breeding sites.)
Most of our local native capers grow on country roadsides. They are prickly plants, so are grown only by butterfly enthusiasts, and tend to be cleared from farms and acreage estates by owners who don’t want to deal with the prickles.

They can also be completely defoliated whenever the butterflies have a big breeding year. They bounce back to beauty and good health afterwards, with all the freshness of a well-pruned plant, but the only people who grow them are those who value the cloud of lovely butterflies more highly than a high standard of year-round perfect beauty from their plants.
Roadsides are potentially subject to clearing for road-building, as our population increases, as well as “beautification” by those who prefer a well-mown, neat and tidy road verge to native vegetation. Depending on your personal aesthetic and philosophical viewpoint, a natural roadside environment is a rich and  environmentally productive ecology, or an ugly “hotch potch”. Unfortunately, destroying a patch of biodiversity is very, very much quicker and easier than replacing it, so the people who think nature needs tidying up, and are prepared to do something about it, have a disproportionate  advantage, when it comes to living in their preferred Australian landscape type.
The long-term future may hold fewer of these spectacular caper white population explosions. Let’s enjoy them while we have them.
For more on this butterfly and its host plants, see my posts for November 19, 2009 and December 4, 2008, or simply type the butterfly’s name into this site’s white search box at top left.

A New Way of Identifying Local Plants

It’s always been a problem.
You see a pretty tree in the local bush, or rainforest, or on your new block of land. You want to find out what it is, but nobody seems to know.
There’s a new tool that has just been released this week, that helps with a big chunk of the problem. It is an interactive identification key, on a USB, called:


It’s available from http://rainforests.net.au or http://www.rainforestpublishing.com.au , where you can also see some good illustrations showing what’s in the program.
The plants it covers are trees (including fern trees and palms), shrubs, climbers, and mistletoes. The definition of “rainforest” is very broad. All our local dry rainforest and scrub plants are in there, even those which are technically of "rainforest type", but grow in obviously non-rainforest situations out on the Downs. You’ll find wilgas, for instance.
The program costs $80.00. My first thought, being a frugal body, is that it is somewhat expensive. However, I had a second thought which is that it contains so very much more than could ever be put into in a single book that’s it’s a bargain. For instance there are over 12,000 photos!
The best thing is the key itself. My experience with conventional plant keys is that I can get lost somewhere in the pick-a-path process. This key, having the advantages of computer technology, lets you arrive at an ID from many different angles.
The keying-out process begins with the total list of plants, all 1139 of them, and every time you add a bit of information, it gets shorter, until you are left with the answer to your question.
First you put in what type of plant you have (tree, climber, palm, etc). At once, the list is shortened as other plant types are subtracted from it.
Then you might put in that your mystery plant has pink fruits. All the plants without pink fruits disappear from the list. Put in a few other characteristics that are obvious to you - maybe the geographical area, the size of the fruits, and the length of the leaves, and you may even end up with just your target plant left on the list already!
If you haven’t got there yet, there are loads of other questions you can answer to work towards an ID. At first some of these can look daunting. Is the leaf elliptic, ovate or lanceolate, for instance? What do the words mean?
No worries, clicking on a little icon next to the words brings up an illustrated description of all the leaf shapes, so you can easily find the word that best matches your plant sample.
The plant descriptions are also a help. Each plant name in the list has little icons beside it.
Clicking on them brings up a written description with photos, and a black and white sketch showing important identifying features. The pictures are a help when you have got the list of possible plants down to the last few, but can’t decide which one is your unidentified plant.
The other great thing is that there is a species index. You click on a plant name that interests you, and by the time you’ve read the description and looked at the photos of the whole plant, plus close-ups of the trunk, flowers, fruits, leaves (both sides) and so on, you really feel you know the plant.
Great stuff!

Cuttsia

Cuttsia viburnea
Family: CARPODETACEAE
Now flowering - and what attention-grabbing flowers these are!

In their typical habitat, a shady creek bed in rainforest understorey, these gleaming white flowers led my eyes to a plant I might otherwise have overlooked. The strong honey scent of their nectar-rich flowers was attracting the attention of many insects. Little quiet birds were coming as well, to feed on the insects, making the point that insect-attracting plants have value not only for the insects in their environment.
If fertilised, the flowers of this plant produce heavy seed crops in their little capsules. However,  as with many bisexual-flowered plants, Cuttsia plants are not self-fertile. Separate timing of the maturing of their flowers' male and female parts means that the flowers of isolated plants remain unfertilised, despite visits from many suitable pollinators.To produce seeds it must grow close to a friend or two.

A solitary plant makes a lovely garden specimen, but seed production matters if we are trying to re-introduce lost ecosystems or reproduce something like a natural environment in our own gardens. Don’t overlook the possibility of planting several quite close together if space is limited. This would result in something resembling a multi-stemmed large shrub or small tree.
Cuttsias grow best where there is constant soil moisture. Where this can be provided, this is an excellent plant for an understorey situation or a shady corner. Established plants do tolerate some drought, but would need to be helped along if the dry spell is prolonged.
They are claimed to be frost hardy.

There have been a few attempts to give this plant a “common” name. Some people call it elderberry (but it’s not an elderberry, and Australia has several genuine elderberry species which might even be growing side by side with this plant in the wild). Others call it native hydrangea (but it isn’t related to hydrangeas, and doesn’t resemble them much, as you can see). The name “native hydrangea” is more commonly used for the closely related Abrophyllum ornans, so like “elderberry, is not a particularly practical one. Others call it honey flower, which is very appropriate considering its strong nectar scent. Unfortunately, if you say “honey flower”, people are more likely to think you are speaking of another Australian plant, Lambertia formosa. Falling back on the botanical name, as we have done for grevilleas and quite a few other Australian plants, seems the best solution to achieving a user-friendly name for everyday use.