Pinus elliottii
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Pinus elliottii var. Densa |
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| Pinus elliottii | ||||||||||||
| Engelm. |
Pinus elliottii is an evergreen conifer from the genus of pine ( Pinus ) with mostly 18 to 25 centimeters long needles, usually arranged in groups of two or three, and 9 to 15 centimeters long seed cones. The natural range is in the southeastern United States and extends to the south of Florida and the Florida Keys . Adistinction is made betweentwo varieties . The species is not endangered and an economically important supplier of resin and wood, but is rarely used in horticulture.
description
Appearance
Pinus elliottii grows as an evergreen tree up to 30 meters high. The trunk is straight or twisted and reaches a chest height diameter of up to 80 centimeters. The trunk bark is orange-brown to purple-brown and breaks into large, irregularly rectangular, thin paper-like or scaly plates, which are separated by irregular cracks. The branches are horizontal and form a wide, dome-shaped, open crown. The needled branches are strong, often up to 1 centimeter thick, initially orange-brown and later red-brown to dark brown. They are rough after losing the needles from permanent pulvini .
Buds and needles
The buds are egg-shaped-cylindrical to cylindrical, 1.5 to 2.0 inches long and not resinous. The lower leaves , which are designed as bud scales, have a white or silvery edge. The needles grow in pairs or in threes in a 15 to 20 millimeter long needle sheath and usually stay on the tree for two or three years. They are yellowish green or bluish green, flexible, straight and slightly twisted, rarely from 15, usually 18 to 25 and sometimes up to 30 centimeters long and 1.2 to 1.5 millimeters wide. The edge of the needle is finely sawn, the end short pointed to short pointed. There are narrow stomata lines on all needle sides .
Cones and seeds
The pollen cones grow spirally arranged in groups. They are cylindrical, 3 to 4 inches long, initially purple and later dark or dull brown. The seed cones grow individually or in pairs. They are almost sessile or stalked up to 3 centimeters long, rarely from 7, usually 9 to 15 and sometimes up to 18 centimeters long, closed, narrowly ovate to ovate-elongated and open, broadly ovoid to ovoid-cylindrical with a more or less flattened base. The seed scales are thin and woody, inelastic and light brown. The apophysis is shiny brown, raised and sharply keeled across. The umbo is reinforced with a firm, short spike . The seeds are ellipsoidal, 6 to 7 millimeters long and dark brown. The seed wing is 20 to 30 millimeters long. The seedlings can initially grow grass-shaped.
bark
Needles
Male cones
Branch with needles and seed cones
Chromosome number
The number of chromosomes is 2n = 24.
Distribution, ecology and endangerment
The natural range of Pinus elliottii is in the southeastern United States and stretches from South Carolina to Alabama and Georgia to Mississippi and Louisiana and extends to the south of Florida and the Florida Keys . Outside the natural range, the species was introduced worldwide in subtropical and warm temperate areas. In South Africa it is used for forestry for wood production and is considered an invasive species in the South African province of Mpumalanga . The same applies to low-lying and rather humid areas in Zimbabwe and for areas in Australia. In China, it is grown for forestry in several provinces.
The species grows in humid and warm, subtropical climates at low altitudes. Most of the precipitation takes place in cloudbursts in summer, the mean annual precipitation is around 1270 millimeters. Winters are mild to warm and dry, but frosts can occur on clear winter nights. The distribution area is assigned to winter hardiness zone 9 with mean annual minimum temperatures of −6.6 ° and −1.2 ° Celsius (20 to 30 ° Fahrenheit ). Pinus elliottii often grows in wetlands, such as on sandy islands in large swamp areas such as the Okefenokee Swamp and the Everglades , on the banks of ponds and along drainage channels. However, the roots need aerated soil so that the species avoids actual swamps. In the Florida Keys, the densa variety grows on particularly nutrient-poor karst , which was formed from old coral banks. Pinus elliottii forms pure stands or grows together with the frankincense pine ( Pinus taeda ), with Pinus serotina , the white false cypress ( Chamaecyparis thyoides ), the bald cypress ( Taxodium distichum ) and various deciduous trees such as the black tupelo tree ( Nyssa sylvatica ), the water -Tupelo tree ( Nyssa aquatica ), the swamp magnolia ( Magnolia virginiana ) and Persea borbonia . The undergrowth is often formed by bushy palm trees such as the palmetto palm ( Sabal palmetto ) and the saw palmetto ( Serenoa repens ). The seedlings of the densa variety initially grow grass-shaped as an adaptation to the frequent ground fires. They hardly show any increase in height, but form an extensive root system. After a fire, the young plants form new buds on the stems close to the bottom. In this phase photosynthesis takes place exclusively with the grass-shaped leaves. After a few years there is a surge in height growth, which brings the growth zone over the area at risk from fire without branches forming. Only then are twigs and the usual needling done.
In the Red List of the IUCN is Pinus elliottii classified as endangered ( "Lower Risk / least concern"). However, it should be noted that a reassessment is necessary.
Systematics and research history
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Pinus elliottii is a species from the genus of the pines ( Pinus ), in which it is assigned to the subgenus Pinus , section Trifoliae and subsection Australes . It was first scientifically described in 1880 by George Engelmann . The generic name Pinus was already used by the Romans for several types of pine. The specific epithet elliottii honors the botanist Stephen Elliott (1771-1830), who was the first to classify it as a separate taxon that can be distinguished from the frankincense pine ( Pinus taeda ). A synonym of the species is Pinus heterophylla (Elliott) Sudw.
The species forms hybrids with Pinus echinata , the swamp pine ( Pinus palustris ) and the frankincense pine ( Pinus taeda ), which are also of forestry importance. Crossing attempts with the sand pine ( Pinus clausa ) and the pitch pine ( Pinus rigida ) were more difficult to implement but also successful. It is closely related to the Caribbean pine ( Pinus caribaea ), with which it can form natural hybrids when the two species grow together.
Two varieties are recognized, which differ mainly in the nature of the wood and a "grass stage" of the seedlings:
- Pinus elliottii var elliottii : The needles usually grow in threes in a needle sheath, the hypodermis consists of two to three layers of cells, and three to five resin canals are formed per needle . The base of opened tenons is more or less trimmed. The seedlings do not form grass-like shapes, but develop evenly after germination with regular internodes and branches. The distribution area stretches from South Carolina to Mississippi and extends in Florida to the Everglades from sea level to heights of 150 meters. The variety is classified as not endangered.
- Pinus elliottii var. Densa Little & KWDorman : The needles grow more often in pairs than in threes, the hypodermis usually consists of three to four, rarely two or five cell layers and up to nine resin canals are formed per needle. The base of opened tenons is rounded. The wood is heavier and harder than that of the elliottii variety . Initially, seedlings usually grow grass-like with smaller stems and with crowded, almost terminal buds. The growing trunk does not initially form branches. The distribution area is in the south of Florida and extends along the coast to central Florida, furthermore the variety grows on eight of the Lower Florida Keys . It grows at heights of up to 10 meters above sea level. The variety is classified as not endangered. Neither the wood nor the resin are used economically. Pinus elliottii var. Densa was first described in 1952 by Elbert Luther Little and Keith William Dorman . The taxon was discovered in 1982 by Albert Edward Murray as the subspecies Pinus elliottii subsp. densa and classified by John Silba as a separate species Pinus densa in 1984 , but neither is recognized. The two names are therefore only synonyms.
use
Pinus elliottii is a major supplier of resin products used in the maritime industry to waterproof boats and to tar rigging . The trees have been resinated since colonial times , the peak of resin production was reached in 1930. Since then, production has fallen sharply, but trees are still resinified until they are 20 years old, after which their wood is processed into cellulose . Particularly resin-rich trees were grown through selection, the seedlings of which were exported to many tropical countries.
The species is increasingly being planted in plantations and is an important supplier of wood and pulp. It is also cultivated outside of its natural range both in the United States and in subtropical and warm temperate areas of other countries. The wood is often preserved and used as round wood, for example for the production of posts. The bark and the needles are used as mulch in horticulture, the species itself is rarely planted in gardens.
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literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 670-672 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 430 .
- Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico . Volume 2: Pteridophytes and Gymnosperms . Oxford University Press, New York / Oxford a. a. 1993, ISBN 0-19-508242-7 (English).
- Wu Zheng-yi, Peter H. Raven (Ed.): Flora of China . Volume 4: Cycadaceae through Fagaceae . Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 1999, ISBN 0-915279-70-3 , pp. 20 (English).
- Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , p. 487 (reprint from 1996).
Individual evidence
- ↑ a b c Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 670
- ^ A b c Robert Kral: Pinus elliottii in Flora of North America , Volume 2
- ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, pp. 670-671
- ↑ a b c Robert Kral: Pinus elliottii var.elliottii in Flora of North America , Volume 2
- ↑ a b c d e f Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 671
- ^ A b c Pinus elliottii in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved May 4, 2013.
- ↑ a b Christopher J. Earle: Pinus elliottii. In: The Gymnosperm Database. www.conifers.org, November 27, 2012, accessed May 4, 2013 (English).
- ^ Liguo Fu, Nan Li, Thomas S. Elias, Robert R. Mill: Pinus elliottii , in Flora of China , Volume 4, p. 20
- ↑ Pinus elliottii in the endangered Red List species the IUCN 2012. Posted by: Conifer Specialist Group, 1998. Accessed May 4, 2013.
- ↑ Exactly: Etymological dictionary of botanical plant names p. 487
- ↑ a b James E. Eckenwalder: Conifers of the World , p. 430
- ↑ Pinus elliottii. In: The Plant List. Retrieved May 4, 2013 .
- ^ A b Robert Kral: Pinus elliottii var.densa in Flora of North America , Volume 2
- ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 672
Web links
- Pinus echinata at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed May 4, 2013.