The heterokonts or stramenopiles are a major line of eukaryotes presently containing about 10,500 known species.(External Link) Most are algae, ranging from the giant multicellular kelp to the unicellular diatoms, which are a primary component of plankton. Other notable members of the Stramenopila include the (generally parasitic) oomycetes, including Phytophthora of Irish potato famine infamy and Pythium which causes seed rot and damping off. Chloroplasts Heterokont algae are chromists with… (More on Heterokont)