Nicotiana sect. Polydicliae
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Nicotiana sect. Polydicliae is a section of the tobacco genus ( Nicotiana ). There are two types of it .
description
Species of the Polydicliae section are herbaceous , annual plants . Occasionally they form native rosettes . The leaves are short stalked, the stem leaves are often sessile.
The flowers open at night. The crown is radially symmetrical, salver-plate-shaped and colored white. The corolla tube is straight, the corolla lobes pointed.
The types of the section are allopolyploid , their chromosome number is n = 24.
distribution
The species are common in the southwestern United States and Mexico .
Systematics
Only two types are counted in the Polydicliae section :
- Nicotiana clevelandii A. Gray
- Nicotiana quadrivalvis Pursh
It is believed that the section originated about 1 million years ago from the ancestors of the diploid species Nicotiana obtusifolia as the male parent and the ancestors of Nicotiana attenuata as the female parent.
proof
literature
- Sandra Knapp, Mark W. Chase and James J. Clarkson: Nomenclatural changes and a new sectional classification in Nicotiana (Solanaceae) . In: Taxon , Volume 53, Number 1, February 2004. pp. 73-82.
Individual evidence
- ↑ K. Yoong Lim et al .: Sequence of events leading to near-complete genome turnover in allopolyploid Nicotiana within five million years. In: New Phytologist , Volume 175, Issue 4, 2007. doi : 10.1111 / j.1469-8137.2007.02121.x
- ↑ Ales Kovarik et al .: Evolution of rDNA in Nicotiana Allopolyploids: A Potential Link between rDNA Homogenization and Epigenetics . In: Annals of Botany , Volume 101, Issue 6, 2008. pp. 815-823. doi : 10.1093 / aob / mcn019