Alternanthera echinocephala
Alternanthera echinocephala, known as spiny-headed chaff flower, is a shrubby plant in the family Amaranthaceae native to the Galápagos Islands, mainland Ecuador, and Peru. Its relatively large spiny "heads" of flowers distinguish it from other species of "Alternanthera" found in the Galápagos. Description. "Alternanthera echinocephala" is a much-branched shrub up to tall. Its leaves are arranged oppositely and are narrow and pointed (lanceolate) with untoothed margins, long. The flowers are grouped into somewhat rounded spikes ("heads") about across. Each flower has one large and two small bracts below it, which form the most conspicuous part of  the flower head. The bracts are greenish-white, sometimes with pinkish tones. The small sepals are similar in colour, only long. The flowers have no petals and five stamens. Thirteen species of "Alternanthera" are found in the Galápagos Islands, of which six are endemics; "A. echinocephala" is said to be easy to distinguish based on its relatively large flower heads with their spiny appearance. Taxonomy. The species was first described in 1847, from the Galápagos Islands, by Joseph Dalton Hooker as "Brandesia echinocephala". Paul Carpenter Standley transferred it to the genus "Alternanthera" in 1932. The specific epithet "echinocephala" is derived  from the Greek words "echinos", hedgehog or sea urchin, hence meaning "spiny", and "cephalos", here meaning "headed". Distribution and habitat. , Tropicos shows the species to be distributed in the Galápagos Islands and the coast of mainland Ecuador. McMullen (1999) says that it is also known from Peru. Within the Galápagos, it is known from the islands of Española, Floreana, Isabela, Pinta, Pinzón, San Cristóbal, Santa Fe and Santiago, as well as from some of their neighbouring islets. It is a plant of the arid lowland regions of the Galápagos.