Selenicereus wittii
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Selenicereus wittii |
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| ( K.Schum. ) GDRowley |
Selenicereus wittii is a species of plant in the genus Selenicereus from the cactus family(Cactaceae). It is one of three species of cactus found in the central Amazon basin . Their epiphytic place of growth on the trunks of the bank trees of the Igapó rivers is regularly flooded for a few weeks. During this time, the seeds will spread through the water, which is unique to the cactus family.
It was first described in 1900 by Karl Moritz Schumann . The second part of the scientific name , the epithet of the species, honors the German businessman and hobby plant collector Nikolaus Heinrich Witt, who discovered the species.
description
Vegetative characteristics
Selenicereus wittii grows as a epiphyte creeping and climbing trees. The richly branched, leaf-like, flattened shoots are phyllocladia , which are pressed tightly to the tree trunks of their carriers and form aerial roots along their midrib . When exposed to direct sunlight, the elliptical to lanceolate, dark green shoots turn dull red due to strong betalain pigmentation and are therefore clearly visible from a distance. They are up to 60 centimeters long, 6 to 14 centimeters wide and are only 2 to 4 millimeters thick. At their slightly notched edges are areoles covered with white wool at a very close distance of 5 to 10 millimeters . Up to 20 needle-shaped, yellowish-brown thorns up to 12 millimeters in length arise from the areoles .
blossoms
The salver-shaped flowers are up to 27 centimeters long and reach a diameter of 12.5 centimeters. The long, slender flower tube measures just 9 millimeters in diameter. It tapers towards the top and is only about half as thick there as at the base. Your inflorescence is spread out flat. The more or less identically shaped and colored bracts are pure white and reflect intense ultraviolet light . The pericarpel and the flower tube are scaly and covered with hair-like thorns. The approximately 10 outer bracts are linear and about twice as long as the inner, oblanceolate, pointed or long-pointed bracts.
The nectaries sitting on the flower base secrete a large amount of clear nectar . The ovary consists of 10 to 14 carpels . The leaves and fruit of the lower part of the stylus are warty . The stamens do not protrude beyond the inner bracts. In contrast to the other species of the genus Selenicereus , whose stamens usually form tricolpate pollen grains , the pollen grains of Selenicereus wittii are hexacolpat, that is, they have six instead of three germ folds distributed on the surface of the pollen grains.
In its natural location, Selenicereus wittii blooms in May, in greenhouse cultivation, however, in the months from November to February. The flowers only open for one night. The flower opening begins after sunset. The flower is fully open within two hours. It closes again at sunrise. Until the blossoms are fully open, the blossoms initially give off an intense fragrance, which eventually turns into an unpleasant odor. The components responsible for the odor have been identified as benzyl alcohol , benzyl benzoate and benzyl salicylate .
Fruits and seeds
The fruits are elongated, greenish and thorny berries about 3.5 centimeters long. They mature in about a year in their natural location and then tear open along a longitudinal opening. The pulp contained is rather dry.
The shell-shaped, glossy black-brown seeds are about 4 millimeters long and 2 millimeters wide. This makes them unusually large for seeds of the cactus family. The navel and the germinal cavity of the seeds are united. The seed coat is almost smooth. The main part of the seed consists of a layer of greatly enlarged, dead cells that are on the top and that are filled with air, which allows the seeds to float in water.
ecology
pollination
Certain flower characteristics, for example the pure white color, the extreme shape of the serving plate, the scent and the nocturnal opening, indicate that the flowers are pollinated exclusively by hawkers . However, pollination has not yet been observed in nature. Due to the length of the flower tube, only the two species Neococytius cluentus and Amphimoea walkeri come into question, which have a proboscis up to 25 centimeters and occur in the natural range of Selenicereus wittii .
Spread
The structure of the seeds with their large, air-filled, outer cells of the seed coat differs from all other types of cactus. The propagation of the buoyant characterized seeds carried by the water ( Hydrochorie ). The epiphytic orchid species Galeandra devoniana, which also lives in the Igapó forests of the Rio Negro, spreads in this way , as does the sundew Drosera amazonica .
distribution
Selenicereus wittii is common in the rainforests of the central Amazon basin along black water rivers . There the species grows in abundance in the crown area of the temporarily flooded floodplain forests. The distribution area extends along the Rio Negro and Rio Japurá in Brazil via the Río Vaupés , Río Apaporis and Caquetá in Colombia to northeast Peru in the Loreto region to the city of Iquitos and probably includes the southern area of the Amazon basin in Venezuela . In addition to Selenicereus wittii , only the two cactus species Rhipsalis baccifera and Epiphyllum phyllanthus grow there .
Botanical history and systematics
Selenicereus wittii was discovered in 1899 in the Igapó forests of the Rio Negro near Manaus by the German businessman and hobby plant collector Nikolaus Heinrich Witt. He sent a plant to Karl Moritz Schumann in Berlin-Dahlem , who initially could not classify it taxonomically . Only when Schumann received further specimens from Witt in autumn 1900 and discovered fruit on them, he was able to assign them to the genus Cereus and publish the first description as Cereus wittii . With the choice of the species name, Schumann honored the discoverer of the species.
Nathaniel Lord Britton and Joseph Nelson Rose created the monotypical genus Strophocactus in 1913 with the only species Strophocactus wittii . They derived the botanical name of the genus from the Greek noun στροφή strofe for "twist, twist" because of the shoots wound or twisted around the stems . Gordon Douglas Rowley finally placed the species in the genus Selenicereus in 1986 due to its flower structure .
The plant illustrator Margaret Mee (1909–1988) was able to observe and draw the species in its wilderness. The only detailed investigation of Selenicereus wittii so far was carried out in 1997 by Wilhelm Barthlott and his colleagues. Through this investigation numerous details about the biology, ecology and distribution of Selenicereus wittii could be clarified. However, the systematic position of the species is still unclear. Ralf Bauer suggested in 2003 that the genus Strophocactus should be recognized again and that Selenicereus wittii should be re-classified in this genus.
proof
literature
- Edward F. Anderson : The Great Cactus Lexicon . With a foreword by Wilhelm Barthlott and an article by Roger Brown on cactus cultivation and care. Translated from English, supplemented and revised by Urs Eggli. Ulmer , Stuttgart 2005, ISBN 3-8001-4573-1 , p. 594 (English: The cactus family . Portland 2004. Translated by Urs Eggli ).
- Curt Backeberg : Die Cactaceae: Handbuch der Kakteenkunde . 2nd Edition. tape II . Gustav Fischer Verlag, Stuttgart New York 1983, ISBN 3-437-30381-3 , p. 770-771 .
- Wilhelm Barthlott, Stefan Porembski, Manfred Kluge, Jörn Hopke, Loki Schmidt: Selenicereus wittii (Cactaceae): An epiphyte adapted to Amazonian Igapó inundation forests . In: Plant Systematics and Evolution . Volume 206, pp. 175-185, 1997; doi: 10.1007 / BF00987947
- Nadja Biedinger: Selenicereus wittii - a rare epiphytic cactus from Amazonian rainforests . In: Cacti and other succulents . Volume 53, No. 6, pp. 160-162, 2002
- NL Britton , JN Rose : The Cactaceae. Descriptions and Illustrations of Plants of the Cactus Family . tape II . The Carnegie Institution of Washington, Washington 1920, p. 221-222 .
Individual evidence
- ↑ a b c Wilhelm Barthlott et al. P. 182
- ↑ F. Rivadavia, A. Vicentini, A. Fleischmann: A new species of sundew (Drosera, Droseraceae), with water-dispersed seed, from the floodplains of the northern Amazon basin, Brazil . In: Ecotropica . Volume 15, 2009, pp. 13-21.
- ^ Wilhelm Barthlott et al. Pp. 175 and 183
- ↑ Nadja Biedinger p. 160
- ↑ The Gardeners' Chronicle . 3rd series, vol. 21, p. 79, London 1901; cited in NL Britton, JN Rose: The Cactaceae p. 222
- ^ Karl Moritz Schumann: Cereus wittii K.SCH. In: Monthly for cactus science . P. 153, Berlin 1900
- ^ NL Britton, JN Rose: Studies in Cactaceae . In: Contributions from the United States National Herbarium Volume 16, 1913, p. 262 , plate 84 .
- ^ Gordon Douglas Rowley: Stoye postcards and the Haage connection . In: Excelsa . Volume 12, p. 36, 1986
- ↑ Tony Morrison: Journey Fifteen: 1988 - The Moonflower . In: Margaret Mee: In Search of Flowers of the Amazon Forests: Diaries of an English Artist Reveal the Beauty of the Vanishing Rainforest . Nonesuch Expeditions Ltd., 1988, pp. 280 f., ISBN 1-869901-08-8
- ↑ Nadja Biedinger p. 161
- ↑ Ralf Bauer: A synopsis of the tribe Hylocereceeae F. Buxb. In: Cactaceae Systematics Initiatives: Bulletin of the International Cactaceae Systematics Group . Volume 17, 2003
