Tuber excavated by Alectura lathami Australian scrub turkey
The narrow-leaf cotton bush looks the closest of the suggested species. I'm basing it largely on the appearance of the fruit but the flowers look like they may also match, though the photo of the flowers is unfortunately not clear. The species has also been identified on Ash Island once before.
A number of these plants were growing along the edge of the road across Ash Island. They were growing in the long grass in open areas between the mangrove forests and casuarina forests. Most of the island is swampy. They were all roughly the same height which I assume would be about chest height on me, maybe 140cm high.
The fruit looked like the texture of a choko, though we didn't touch them to confirm. The fruit had long flexible-looking spikes covering them. The flowers were white and growing in small clumps on the branch.
Fallen rainforest fruit about the size of an apricot. Fairly firm.
Fallen rainforest fruit.