Compass plant
| Compass plant | ||||||||||||
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Compass plant ( Silphium laciniatum ) |
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| Silphium laciniatum | ||||||||||||
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The compass plant ( Silphium laciniatum ) is a species of the sunflower family (Asteraceae).
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description
The compass plant grows upright and reaches heights of 40-100- (300) centimeters. The stems are round, hairy or glabrous. The leaves are stalked or sessile, their leaf blades are partially lobed or lanceolate, egg-shaped or rhombic or linear. The bracts of the flower heads are 25–45 in 2–3 rows. They are pressed against or bent back. The 27–38 ray-florets and the 100–275 tubular florets are yellow.
The number of chromosomes is 2n = 14.
Physiological adaptation
The plant grows on the prairies of the USA . It can adjust its vertically aligned leaves in a north-south direction to adapt to strong sunlight. The leaf tips then usually point in north-south direction, while the leaf blades point east or west. Experiments have shown that the rate of photosynthesis and thus the CO 2 - Assimilation Although in the horizontal position of the sheets is as large as at the vertically displayed in the North-South direction of the profile, but that water consumption is substantially greater in the midday sun. If the leaves were positioned in an east-west direction, the CO 2 assimilation would be lower.
With this leaf orientation, Silphium laciniatum is one of the representatives of the compass plants . The English names are prairie compass plant or compass flower .
literature
- Thomas W. Jurik, Hanzhong Zhang and John M. Pleasants: Ecophysiological consequences of non-random leaf orientation in the prairie compass plant, Silphium laciniatum. In: Oecologia, Volume 82, Number 2, Springer, Berlin / Heidelberg, February 1990, pp. 180-186, summary at Springerlink
- Bruce A. Ford: Silphium Linnaeus . In: Flora of North America, vol. 21 . Online .
Individual evidence
- ↑ Silphium laciniatum at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
