ESPOSTOA

Autor: Britton & Rose

• ETYMOLOGY
A genus honouring Nicolas Esposto (1877-?), Peruvian botanist of Italian origin, founder of the National School of Agriculture of La Molina, Lima, Peru. Portrait is unknown.
• DESCRIPTION
A genus of bushy or treelike plants, branching usually from the base or halfway up, with columnar stems having numerous ribs. Spines sturdy or hairy, sometimes covering the epidermis. Cephalium appearing laterally on adult reproductive stems.
Flowers nocturnal, usually self-sterile, tubular or bell-shaped, whitish to creamy yellow, outer tepals yellowish to pink, usually with a bad odour (for humans!), floral tube very short, scaly but not spiny, pollinated by bats (Anoura geoffroyi and Glossophagasoricina), but also by bees and hummingbirds (Espostoa mirabilis, Rauh 1958, Vogel 1968 in Emerson 2007). Fruits globose to egg-shaped, juicy, naked or bearing tufts of hairs, floral remains persistent. Seeds variable according to species, generally black and shiny, finely pitted.
• HABITAT
The genus Espostoa grows between 450 m and 2800 m or more in altitude, in rocky coastal valleys and canyons west of the Andes, sometimes on mountain steep slopes, on hills, among rocks, often among the low-growing vegetation, together with Bromeliads, in woodlands, sometimes lush forests (￡. utcubambensis) and often forms dense populations.
• DISTRIBUTION
Ecuador (Azuay-EI Oro, Loja), Peru (Amazonas, Ancash, Cajamarca, lea, La Libertad, Lambayeque, Lima, Piura).

Currently 11 recognised species + 3 subspecies:
– Espostoa calva* F.Ritter 1981
– Espostoa frutescens J.E. Madsen 1989
– Espostoa huanucoensis* HJohnson ex F.Ritter 1981
– Espostoa hylaea* F.Ritter 1964
– Espostoa lanata* (Kunth) Britton & Rose 1920
– Espostoa lanata subsp. lanianuligera* (Ritter) G.Charles 2002
– Espostoa lanata subsp. ruficeps (Ritter) G.Charles 2002
– Espostoa laticornua* Rauh & Backeb. 1957
– Espostoa melanostele* (Vaupel) Borg 1937
– Espostoa melanostele subsp. nana* (Ritter) G.Charles 2002
– Espostoa mirabilis* F.Ritter 1964 (not Haagespostoa mirabilis)
– Espostoa ritteri* Burning 1960 (not Haagespostoa ritteri)
– Espostoa superba* F.Ritter i960
– Espostoa utcubambensis G.Charles 2003

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