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Origin and Habitat: Haageocereus tenuisSN|31691]]SN|31691]] grows between Chancay and Huacho (Parque de las Leyendas), north of Lima, Peru. Haageocereus tenuisSN|31691]]SN|31691]] has an extremely restricted range. In 2004 the population consisted of 504 individuals spread over 3 square kilometers.
Altitude range. 200 to 250 metres above sea level.
Habitat and Ecology: This species grows on shifting sand dunes in a very arid coastal habitats (lomas costeras). The prostrate creeping stems are usually covered by wind-blown sand and pieces of shells. It may experience moisture when a fog rolls off the ocean, or when it rains only every two years. It is close to the Pan-American Highway and therefore threatened by both collectors and development. Haageocereus tenuisSN|31691]]SN|31691]] grows in an area being taken over increasingly for poultry farming. Surveys have shown that the population is now only 30% of the figure ten years ago, and this impact has not ceased and is not reversible. The species thus qualifies for listing as Critically Endangered.
- Haageocereus tenuis F.Ritter
Haageocereus tenuis F.Ritter
Kakteen Südamerika 4: 1421 (fig.). 1981
- Haageocereus tenuis F.Ritter
- Haageocereus lanugispinus F.Ritter
- Haageocereus lanugispinus f. cristatus hort.
ENGLISH: Strong cactus
Description: Haageocereus tenuisSN|5625]]SN|31691]] is a prostrate and creeping cactus densely covered by greyish spines with microscopic hairs that survives in extreme conditions in northern Peru. It grows on its side, branches splayed forlornly, its base decaying in the loose sand. The sides of the stems produce roots that store water, which is rarely available.
Derivation of specific name: Lat. tenuis', thin, slender, presumably refers to appearance of the stems.
Stems: Cylindrical, thin, slender, grey to bluish green, 1.5-3 cm in diameter. These stems develops adventitious roots in contact with the ground and later detach from the mother plant.
Ribs: 12-15 with wavy margins.
Areoles: Silver-gray, close set.
Spines. Minute, greyish with microscopic hairs helping in the capture of humidity from fog.
Central spines: 7-10, stout, brownish to black, to 20 mm long.
Radial spines: About 30, white to brownish, 2-3 mm long.
Flowers: Rarely and never profusely produced, nocturnal, white, funnelform, white, to 10 cm long and 4.3 cm in diameter. Pericarpels and floral tubes with long white hairs in areoles.
Fruits: Oblong, pinkish red, to 2.5 cm long and 1.7 cm in
diameter; perianth parts persistent.
Remarks: Haageocereus tenuisSN|5576]]SN|31691]] is triploid (an organism that has three copies of every chromosome in the cell nucleus instead of the normal) and propagates asexually through stem fragmentation. It can also propagate via agamospermy (production of seeds without the occurrence of fertilization). Adventitious embryony (production of embryos from normal tissues and not from a fertilised ovule) has also been referred. Asexually produced seeds are viable. All existing individuals from the only existing population are genetically identical and the population likely represents a single clone. H. tenuis is probably of hybrid origin. The tetraploids Haageocereus chalaensis and Haageocereus multicolorispinus and the diploids Haageocereus pseudomelanosteleSN|31691]]SN|5576]] and Haageocereus decumbensSN|31691]]SN|5625]], also with a prostrate habit, are the possible parental species. However H. tenuis is distinct from other congeners and should perhaps be considered a microspecies.
Subspecies, varieties, forms and cultivars of plants belonging to the Haageocereus tenuis group
- Haageocereus lanugispinus F.Ritter: has cylindrical stems 10-20 cm long, 1.2 2 cm in diameter. Spines 30-40 dense, 3-5 mm long, unequal, needle-like, glassy white. Distribution: North of Pativilca, Peru.
- Haageocereus lanugispinus f. cristatus hort.: Crested form. It has its unique dense cover of glassy white spines.
- Haageocereus tenuis F.Ritter: has rooting slender, prostrate stems 1.5-3 cm in diameter. Central spines 7-10 to 20 mm long. Radial spines 30, 2-3 mm long. Distribution: Between Chancay and Huacho, north of Lima, Peru.
Bibliography: Major references and further lectures
8) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
9) Ritter F. 1981. “Kakteen in Südamerika” volume IV (Peru). Spangenberg
(Germany): Friedrich Ritter.
10) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
11) Håkan Sönnermo “Peru: land of deserts, ice, cacti” Acta Succulenta 2(3) [257-362] 2014-10-20
12) Arakaki, M., Ostolaza, C., Cáceres, F. and Roque, J. 2006. “Cactaceae endémicas del Perú.” Revista Peruana de Biología 13(2): 193s-291s.
13) Novoa, S., Ostolaza, C., Ceroni, A. and Castro, V. 2010. “Estatus poblacional de Haageocereus tenuis (Cactaceae).” Quepo 24: 42-47.
14) Ostalaza, C. & Roque, J. 2013. Haageocereus tenuis. The IUCN Red List of Threatened Species 2013: e.T152883A690499. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T152883A690499.en. Downloaded on 10 September 2016.
15) The Plantsman, Royal Horticultural Society, 2002
16) “Issues in Genetic Research: 2013” Edition Scholarly Editions, 01 May 2013
17) George Gafner “Therapy with Tough Clients: Exploring the Use of Indirect and Unconscious Techniques” Crown House Publishing, 01 November 2013
18) Urs Eggli, Leonard E. Newton “Etymological Dictionary of Succulent Plant Names” Springer Science & Business Media, 29 June 2013
19) Ostolaza C, Rauh W. 1990. “Bemerkungen zur Kakteenvegetation der peruanischen Küstenwüste, insbesondere zu Haageocereus tenuis Ritter, einer wenig
bekannten Art.” Kakteen und Andere Sukkulenten 41:40–44
20) Mónica Arakaki, Pablo Speranza, Pamela S. Soltis, and Douglas E. Soltis “Genetic Variability of an Unusual Apomictic Triploid Cactus Haageocereus tenuis Ritter from the Coast of Central Peru” Journal of Heredity 2013:104(1):127–133 Advance Access publication October 1, 2012 <http://jhered.oxfordjournals.org/content/104/1/127.full.pdf
Cultivation and Propagation: Haageocereus tenuisSN|31691]]SN|31691]] necessitate deep pots and a well drained mineral potting mix.
It needs a sufficient amount of air and is susceptible to overwatering, but needs enough water during vegetation.
Frost Tolerance: It tolerate light frost -5 °C and needs to be kept in a cool place during winter rest this is important for the flowers as well as for its health. Without this cool winter period they normally wont get many buds.
Sun Exposure: This species needs a good amount of sun.
Propagation: Usually it is propagated by cuttings and grafting. Grafted plants in culture are most common and sprout strongly. But it is also feasible to root them but they grow much slower on their own roots and takes various years prior to they bloom.
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