March is October down under and although Victoria isn't as harsh as some of OZ,(it rains at the MCG even) the trident may be suffering from a bit of heat/dryness stress which has prompted a scraggly look and what seems to be an early-ish leaf drop. Also not so sure that the Mediterranean type climate you have there is suitable long term for tridents. For instance, acers in general seems to be a problem in Southern California Tridents don't like to be kept particularly dry - a tad on the damp side is better in fact. I've had acer palmatum go into late summer heat shock and drop their leaves as early as August but come back next spring AOK. Tridents are not particularly famous for spectacular leaf colour and display in fall although there are techniques to improve the display I believe. I'd keep it slightly damp over winter and keep an eye on it. Get worried if no buds start to show round August time or the small branches go all brittle and crispy.

I'm not aware of any site that addresses this specifically, but I've seen references to it here and there when people talk about particular plants. Leaf shape is more or less genetically determined, though in some cases the mature and immature leaves have significant differences (Monstera, Syngonium). As for what evolutionary purpose different leaf shapes have, well, some of this you know already. Leaves that are thick and roundish (jade plant, burro's tail) are trying to minimize surface area, to prevent loss of water. Leaves that are deeply lobed or perforated (Monstera, Philodendron selloum) are subject to occasional hurricanes or other forms of intense wind, and benefit from reducing wind resistance (especially since both of those examples also have really brittle stems which are easy to break off). Other plants in hurricane-prone areas have gone with a different strategy and developed flimsy leaves that curl into cones in high winds (Caladium), or developed leaves which are brittle in one direction and tough in others, so they can tear themselves into Philodendron selloum-like leaves immediately in the event of strong winds (banana, bird of paradise). A lot of aroid leaves (Dieffenbachia, Philodendron, Anthurium, Monstera) have rounded leaves with a distinct "drip tip" at the end. I've seen this explained as an adaptation to keep water from building up on the leaves, though I'm not clear on why that would be bad. (You'd have to ask the plants.) Obviously leaves with spines (Agave, Aloe, Pandanus, some bromeliads) are interested in deterring predators of some kind. It's not entirely an answerable question, because there isn't always necessarily a reason. I mean, there's a *reason*, but it might have to do with being eaten by giant ground sloths that went extinct 10,000 years ago, or what color of flower was attactive to an insect that found some other way of making a living and no longer pollinates flowers, or a mountain range suddenly (in geological time) popping up in the middle of a plant's range and separating a small population from the main population. The only thing you can really be certain of is that every change that's happened to the genome of a particular species, *every* change, reproduced better or faster or more broadly than its relatives for some reason or another. Kinda off-topic, but: Currently, the best way to reproduce yourself, if you're a plant, is to be appealing to human beings in some way. There's a whole book about this, _The Botany of Desire: a Plant's-Eye View of the World_, by Michael Pollan, which is one of my favorite books ever, and which I enthusiastically recommend to any Garden Webbers who might be reading. Here is a link that might be useful: The Botany of Desire (Amazon)

I have somewhat the same problem with one that is just sort of "existing". I brought home some Miracle Grow for hibiscus the other day, but haven't applied it. I'd really like some kind of diagnosis on the thing before I start treating it.....a friend suggested that "I wait to see what came up next year." To which my reply was "a dogwood if I don't get some flowers soon." It did flower last year. Help

could be many things, though dropping buds might be a pest. There is a comprehensive list of plant pests and diseases on www.hiddenvalleyhibiscus.com - that would be a good place to start.