• Multicellular brown seaweeds, which are the most common type of seaweed on rocky beaches, some forming kelp forests with fronds up to 50 m long.
• The usually parasitic oomycetes that include Phytophthora, the pseudofungus that caused the great Irish potato famine of 1845, and Pythium, cause of seed rot and damping off in seedlings, which have been confused with fungi because of their filamentous growth form. The inclusion of several groups of ‘pseudofungi’ and ‘water moulds’, especially genera that have been studied long and hard by mycologists over the years (names to look out for are genera like Saprolegnia, Achlya, Albugo, Bremia, Plasmopara), is why the Heterokonta is important to us.
• Numerous protists of major importance, like photosynthetic diatoms, which are a primary component of plankton.
• Numerous groups of chlorophyll-c-containing algae (chlorophyll-c and a number of other pigments found in the Chromista are not found in any group of true plants).
• Several non-photosynthetic groups that feed phagotrophically or absorptively.

This is one of the most actively researched groups of eukaryotes, partly because some biologists doubt that the group is monophyletic, so the components of the group, and its name, are frequently revised.

A few people treat the Chromista as identical in composition with the heterokonts, describe them as stramenopiles, straminopiles or seek to change the name of the kingdom to Straminipila. However, the name Chromista has nomenclatural precedence (see discussion in Cavalier-Smith & Chao, 2006).

Visit http://www.ucmp.berkeley.edu/chromista/chromista.html

Also, visit the Tree of Life project (though at the time of writing they still use the name stramenopile and the page is in need of revision): Sogin, M.L. & Patterson, D.J. (1995). Stramenopiles. Version 01 January 1995 (under construction) at:

http://tolweb.org/Stramenopiles/2380/1995.01.01 in The Tree of Life Web Project, http://tolweb.org/

Reference

Cavalier-Smith, T. & Chao, E.E-Y. (2006). Phylogeny and megasystematics of phagotrophic heterokonts (Kingdom Chromista). Journal of Molecular Evolution, 62: 388-420. DOI: http://dx.doi.org/10.1007/s00239-004-0353-8.