Autor: Britton & Rose

“Short wax candle”, referring to the relatively small size of the stems of the genus.
Monospecific genus growing in dense clumps, with cylindrical, non articulated stems, branching from the base. Ribs many (18-22), low, spines more or less stiff, yellow becoming blackish and covering the epidermis.
Flowers nocturnal (according to Backeberg), opening during the day (according to Anderson), self sterile, appearing near the base, white. Fruits fleshy when mature, reddish, with deciduous spines. Seeds ovoid, small, dark brown. About the flowers; they open at about 9 pm and are closed towards 11 am -noon the following day (J. Menzel, pers. comm.), probably pollinated by the same insects as Jasminocereus (see this genus), but in my opinion, especially by ants (Camponotus sp.), which are active both day and night.
The monotypic genus Brachycereus grows endemically in the Galápagos islands, from sea level up to approximately
500 m in altitude. It forms clumps and grows exclusively on extremely arid areas, in full sun, in the crevices of lava
fields. It is a pioneer plant, among the first ones to colonize the recent lava flows.
Ecuador (Galápagos Islands).

Currently only one recognised species (+ possible subspecies?):
– Brachycereus nesioticus* (K.Schum.) Backeb. 1935

References: "TAXONOMY of the CACTACEAE" -  ISBN 978-84-617-3723-9 (Vol. 1)