Charophyceae

Charophyceae
Scientific classification
Kingdom:	Viridiplantae
Division:	Streptophyta
Class:	Charophyceae

Charophyceae is a taxon of green algae whose exact rank is the matter of some current debate. Some botanists recommend expanding the existing plant kingdom to include charophyceans and chlorophytes^[1] while others consider Charophyceae to be a class within either the divisions Chlorophyta, Streptophytina, or Streptophyta^[2][3][4]. Other systematists classify Charophyceae as a class under division Charophyta, with Chlorophyta remaining a distinct division^[5].

Regardless of the exact classification of charophyceans, the consensus among botanists is that they are the organisms most closely related to embryophytes (land plants)^[1][6]. Many of the complex traits related to sexual reproduction, photosynthesis, and other defining characteristics of plants evolved first in charophyceans; analysis of cpDNA (chloroplast DNA), for instance, reveals that many characteristics of plant chloroplasts evolved first in the charophycean genera Staurastrum and Zygnema^[1][7].

References

1. ^ ^{a b c} Campbell, N. A. & Reece, J. B. 2005. Biology, Seventh Edition. Benjamin Cummings, San Francisco.
2. ^ Hoek, C. van den, Mann, D. G. & Jahns, H. M. 1995. Algae: An Introduction to Phycology. Cambridge University Press, Cambridge. ISBN 0-521-30419-9
3. ^ Streptophytina
4. ^ McCourt, R. M., Chapman, R. L., Buchheim, M. & Mishler, B. D. “Green Plants”. Accessed 13 December 2007
5. ^ Guiry, M.D. & Guiry, G.M. 2007. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. AlgaeBase.org; searched on 13 December 2007
6. ^ Delwiche, C. F. “Charophycean Green Algae”. Accessed 13 December 2007
7. ^ Turmel, M., Otis, C. & Lemieux, C. 2005. The Complete Chloroplast DNA Sequences of the Charophycean Green Algae Staurastrum and Zygnema Reveal that the Chloroplast Genome Underwent Extensive Changes During the Evolution of the Zygnematales. BMC Biology 3:22