Genus Echinodorus-2

Subclass Alismatidae ( Alismatidae )

Order Alismatales ( Alismatales )

Family Alismataceae ( Alismataceae )

Genus Echinodorus — Echinodorus.

Synonymy Table. Genus — Echinodorus (Echinodorus).

The genus Echinodorus includes a huge number of young species that are very similar to each other. Besides, Echinodorus species haven’t been very lucky with botanists trying to bring order to the taxonomy. Revisions of the genus have been undertaken more than once; the most well-known to us are the works of Rataj, 1975 and Haynes & Holm-Nielsen, 1994. After this revision, several new species were described. In late January 2007, Samuli Lehtonen (Lehtonen, S.) published a new monograph dedicated to the genus Echinodorus. The dissertation considers such important aspects as phenotypic plasticity of Echinodorus, distribution range, cytology, ecology, and evolution of the genus. Lehtonen’s revision is based on a balanced approach using a large amount of data – both morphological and genetic. As a result of analyses using various methods and data, Lehtonen obtained several cladograms that differ in details but are very similar in broad terms. The main ideas are as follows:

1) the genus Echinodorus can be divided into two subgenera: Helanthium for E. bolivianus and E. tenellus, and Echinodorus proper.

2) the division into sections adopted by Rataj is rejected as highly speculative. Many species whose genetic and morphological affinity has been proven were previously placed in different sections.

3) the genus Echinodorus includes 28 species. (A total of over 120 new taxa have been described for the genus Echinodorus). E. berteroi; E. bolivianus; E. bracteatus; E. cordifolius; E. cylindricus; E. decumbens; E. floribundus; E. glandulosus; E. glaucus; E. grandiflorus; E. grisebachii; E. horizontalis; E. inpai; E. lanceolatus; E. longipetalus; E. longiscapus; E. macrophyllus; E. martii; E. nymphaeifolius; E. palaefolius; E. paniculatus; E. pubescens; E. scaber; E. subalatus; E. tenellus; E. trialatus; E. tunicatus; E. uruguayensis.

Echinodorus berteroi, Echinodorus bolivianus, Echinodorus cordifolius.

Why Echinodorus plants do not grow.