These are Celosia Spicata. The cylindrical flower spikes look like wheat, which is why they are also known as wheat celosia.
I saw them in the Flower Dome in the Gardens by the Bay. The following information was from a sign beside the plants.
"Celosia spicata, also known as Wheat Celosia, got its common name from it's distinctive, erect flower spikes reminiscent of a sheaf of wheat. Formed out of abundant cylindrical inflorescences on branch tips above the foliage, the spikes may be red, pink, purple of bi-coloured and often develop a metallic silver sheen at their bases."
