Lava cactus

Brachycereus nesioticus is a small clump-forming cactus endemic to the Galápagos Islands and the only species in its genus. It is a pioneer plant, among the first to colonize bare lava flows, forming spiny yellow-brown clumps. Its white to yellowish flowers open during the day. It grows on young volcanic terrain on islands such as Fernandina, Isabela, and Santiago.