Some species are very hard to distinguish from others. In the field guide the most practical features are used in the keys but there is more. Some other books give features that are proved only to be useful in specific situations. There will be room for discussion on these addition features.
N.B. This is especially suitable for identifying new alien species such as Myriophyllum heterophylum).
Several other aquatic macrophyte species are grown in aquaria and ponds. How to recognize and identify them if they are found outdoor?
There are many more synonyms in use, especially among breeders and traders. An attempt will be made to give an overview of all names in use, including unjust names.
The original keys used many more features than finally were printed in the book. One reason was to reduce the space needed, but the short keys had the supplementary advantage that they were faster in use and the change of mis-identification hardly increased. It is considered to publish these extended keys anyway as on this website, but all depends on interest shown by potential users.
At the moment the keys are being translated to English. See Keys for further information.
Increasing covered geographical area
The field guide covers only species found or expected in The Netherlands. There is an increasing interest to include more species and increase the area covered by the keys to larger parts of Europe. We are studying on ways to develop these keys interactively with other specialists on this website. Are you interested in getting involved? Please send an email.
There is a lot of confusion about taxonomy in some groups. In The Netherlands various species lists circulate, as well as in some other European countries. A European standard does not (yet) exist, but is very needed for international exchange (for instance in the intercalibration process demanded in the Water Framework Directive). Possibly this website can help in developing a European standard. Suggestions are very welcome