Erythrina acanthocarpa flowers and buds

Erythrina acanthocarpa short buds and elongated flowers appear together in the same inflorescence. They have coarse green or brown, cup-shaped to short, tubular, flat-rimmed calyces that are about identical in size and shape. The dense flower cluster is structurally a raceme but so short that it appears spherical. Every flower has a short pedicel remaining unseen, therefore debatable. The lowest flowers open first.

The standard petal or banner dominates in each flower, biggest and conspicuous. Greenish veins run more or less visibly across the creamy part. At this early stage the standard petal completely envelops the rest of the flower, i.e. wing and keel petals as well as the vital parts.

The red stripe visible on the tip of each creamy yellow corolla section is where a slit visibly opens in the folded banner petal (and down the side), when the flower is ready for pollinator visitors. This is when the reproductive parts that need attention are revealed, exserted beyond the corolla. A fully open flower has a long, pale style exserted far and shorter stamens showing their red filaments and small, yellowish anthers (Coates Palgrave, 2002; Gledhill, 1981; iNaturalist).