Genus honouring Ludwig G.K. Pfeiffer (1805-1877), German doctor, botanist, physicist and malacologist, author of Enumeratio Cactearum (see portrait above, public domain).
A genus of mainly epiphytic, epilithic or terrestrial plants, erect to pendulous, with branched stems, segments of indeterminate size, branching in the middle (mesotony) of stems, which are variable, angled or flattened, not tuberculate, with marginal areoles having small scales. Spines small, setose to acculate.
Flowers diurnal, sometimes self-fertile, appearing laterally, sometimes numerous, funnel-shaped, usually yellowish, orange or white, pollinated by insects and hummingbirds. Fruits globose, spiny, setose or naked, translucent and veined, whitish, brownish, olive green, pinkish or red orange, sometimes keeping the remnants of the dried perianth. Seeds black, shiny, elongated, with a branched or long-tailed funicle (typical in this genus).
The genus Pfeiffera grows epiphytically in trees, or on rocks (epilithic) in pockets of humus from 600 m up to on 2700 m in altitude, together with bromeliads, orchids and ferns.
Argentina (Catamarca, Jujuy, Salta, Tucuman), Bolivia (Chuquisaca, Cochabamba, La Paz, Santa Cruz, Tarija).
Currently 6 recognised species + one subspecies:
– Pfeiffera asuntapatensis* (M.Kessler, Ibisch & Barthlott) R.Bauer 2005
– Pfeiffera boliviana* (Britton) D.R.Hunt 2002
– Pfeiffera ianthothele* (Monv.) F.A.C.Weber 1898
– Pfeiffera miyagawae* Barthlott & Rauh 1987
– Pfeiffera monacantha* (Griseb.) P.V.Heath 1994
– Pfeiffera monacantha subsp. kimnachii (Doweld) Ralf Bauer 2005
– Pfeiffera paranganiensis* (Cardenas) P.V.Heath 1994
References: "TAXONOMY of the CACTACEAE" - ISBN 978-84-617-3692-8 (Vol. 2)