Spring — the flowering

By September the ranges are running a single, urgent piece of machinery flat out, and everyone in earshot knows it.

The golden run of wattle that opened the cool season is already thinning towards seed, but it hands the display straight on: the native pea-flowers — the yellow-and-red, unmistakably pea-shaped blooms of shrubby Fabaceae, packed thick through gully and heath — come into their own across spring, while down in the leaf litter the ground orchids push up their odd, solitary spikes, the drooping greenhoods and the cheerful donkey orchids flowering for a few weeks before vanishing back underground for the rest of the year.

Overhead a second machine is running to the same clock.

Nectar in the Mount Lofty region peaks in this window, the cool half of the year tipping into spring, and the honeyeaters follow it in — feeding, nesting and raising young while the bloom lasts, then drifting away again as the flowers close down for summer (Ford & Paton 1986).

It is not slack timing; a bird that bred to the wrong season would be raising chicks over an empty larder.

The orchids are running a stranger emergency, underground and out of season with everything else.

Each spike you see this spring exists at all only because, months earlier, a dust-fine seed with no food reserve of its own was found by one particular species of fungus and fed by it until it could grow a leaf — greenhoods pairing only with a fungus called Ceratobasidium, donkey orchids only with Tulasnella, a specificity worked out at Adelaide’s own Waite Institute (Warcup 1981).

Dig one up to save it, or scatter its seed on promising dirt without its fungus, and nothing will grow: the flower you are admiring is only ever half the plant.

And underfoot, the pea-flowers are already quietly banking next year’s business.

Many of the same Fabaceae shrubs producing this spring’s colour will, by summer, be shedding hard seed wearing a small fatty parcel built for exactly one customer — an ant, which will haul it underground, eat the bribe and leave the seed buried and planted, part of the roughly 1,500-species ant-sown flora that makes this bush the most heavily myrmecochorous on Earth (Berg 1975).

None of these three machines — flower and bird, orchid and fungus, seed and ant — was built to work together; each runs on the same brief wet-season clock.

Even at the hillside’s most exuberant, the woodland-bird community keeping this whole calendar honest has already lost some ten species to local extinction, with dozens more modelled to follow even if not another tree falls (Szabo et al. 2011) — which is why a loud, flowering spring is not proof that the machinery underneath it is still whole.