Heterokontae sensu Copeland 1956, etc. This contextual clarification is rare, such that when the taxon name is used, it is unclear how it should be understood. The term 'Heterokont' has lost its usefulness in critical discussions about the identity, nature, character and relatedness of the group. The term 'stramenopile' sought to identify a clade (monophyletic and holophyletic lineage) using the approach developed by transformed cladists of pointing to a defining innovative characteristic or apomorphy. A taxonomic concept based on a synapomorphy is independent of the organisms that are included. It is stable and robust. New findings may lead to the addition, elimination or regrouping of contained taxa. A synapomorphy-based taxonomic concept is invalidated if the apomorphy in question was found to have evolved on more than one occasion (i.e. is not monophyletic). At the time of writing, the concept of the taxon Heterokont, as used by some, has evolved to align with that of Stramenopiles. The presumed apomorphy of tripartite flagellar hairs in stramenopiles is well characterized. The basal part of the hair is flexible and inserts into the cell membrane, the second part is dominated by a long stiff tube (the 'straw' or 'stramen'), and finally the tube is tipped by several delicate hairs. The proteins that code for the mastigonemes are also well characterized. As far as we know, these proteins are exclusive to the stramenopile clade, and are present even in taxa (such as diatoms) that no longer have physical hairs. Most flagellates stramenopiles have two flagella that insert subapically or laterally. They are usually supported by four microtubule roots in a distinctive pattern (details to be included later). There is also a transitional helix inside the flagellum where the beating axoneme with its distinctive 9 peripheral couplets and two central microtubules changes into the nine triplet structure of the basal body. The current composition of the 'stramenopiles' can be summarized as: Stramenopiles without chloroplasts Oomycetes (water molds) Hyphochytridiomycetes Developayellids also referred to as Bigyromonadea Bicosoecea Labyrinthulomycetes (slime nets) inclusive of thraustrochytids Opalinesa Proteromonadsea Blastocystis Stramenopiles with chloroplasts - Stramenochromes Axodines (Pedinellids and aplastidic actinophryid heliozoa) Bacillariophyceae (diatoms) Bolidophyceae Chrysomerophyceae Chrysophyceae (golden algae) Dictyochophyceae Eustigmatophyceae Olisthodiscophyceae , 2021 Pelagophyceae Phaeothamniophyceae Phaeophyceae (brown algae) Pinguiophyceae Raphidophyceae Synchromophyceae Synurophyceae Xanthophyceae (yellow-green algae) The name of the taxon has also been written as Straminopiles, or more formally as Straminipila. The name "stramenopile" has been discussed by David (2002). In terms