X Haagespostoa is a natural hybrid (nothogenus) between Haageocereus and Espostoa exclusively found in Peru. Backeberg took this taxon for a new genus, and described it as Neobinghamia. According to Ostolaza (Quepo 2009), five taxa are known, all situated west of the Andes. It seems that we must take more seriously the phenomenon of natural hybridization in plants in general and cacti in particular..
The study of reticulate evolution within a genus is promising for the knowledge of Cactaceae, and the propensity to find intergeneric hybrids requires us to pursue even further investigations in this domain. Having used the same epithets identical to Espostoa for two of them (E. mirabilis and E. ritteri) is clumsy and confusing; x Haagespostoa mirabilis (supposed hybrid between E. lanata and Haageocereus versicolor) is found in the Olmos valley (Lambayeque), Peru, while Espostoa mirabilis grows in the gorges of the rio Maranon near Balsas (Amazonas). X Haagespostoa ritteri (supposed hybrid between E. nana and Haageocereus pseudomelanostele subsp. chryseus)
is found towards Yungaypampa and Huallanca (Ancash) while Espostoa ritteri lives near Bellavista (Cajamarca) and also in the department of Amazonas. Rowley (2004) found a solution by considering them as synonyms to x Haagespostoa albisetata.
The genusx Haagespostoa grows endemically in Peru on mountainous slopes in rocky masses, in ravines (quebradas) and valleys, between 300 m and 1820 m in altitude. Populations are obviously rare and limited.
Peru (Ancash, Lambayeque, Lima).
Currently 5 supposed taxa:
– x Haagespostoa albisetata* (Akers) G.D.Rowley 1982
– x Haagespostoa climaxantha* (Werderm.) G.D.Rowley 1982
– x Haagespostoa mirabilis (Rauh & Backeberg) Ostolaza 2009
– x Haagespostoa ritteri Ostolaza 2009
– x Haagespostoa villigera* (Rauh & Backeberg) Ostolaza 2005
References: "TAXONOMY of the CACTACEAE" - ISBN 978-84-617-3723-9 (Vol. 1)