Social algae - Naturalist engraving - Ernst Haeckel, Kunstformen der Natur

Engraving reproduction of: Social algae

Original title Melethallia - Gesellige Algetten

Poster of Pediastrum - Primitive algae of the main class of soft algae or green algae (Class Chlorophyceae or Conjugatae)

Illustration from the book Kunstformen der Natur, which is a collection of artistic lithographs of natural sciences published by the German biologist Ernst Haeckel between 1899 and 1904.

This naturalistic illustration is part of an overall style inspired by Ernst Haeckel, which greatly influenced the emerging Art Nouveau movement at the beginning of the ^20th century. This work, illustrating the impressive beauty and great diversity of the biological world, was complemented by a certain amount of scientific information, some excerpts of which are reproduced below.

This information is over 120 years old and some of it may be outdated!

Scientific classification:

 Phylum of Protophytes (Protophyta)
Main class of primitive algae (Zoosporata)
Class of Melethallians (Coenobiotica)
Family Hydrodictyea

Scientific notice (extract) accompanying the poster print of Melethallia - Social algae :

The Melethallians (Coenobiotica) are small, freshwater-dwelling protophytes belonging to the main class Algettes (the so-called "unicellular zoosporous algae", Zoosporata); they differ from other Algettes in that their green cells do not live in isolation (Monobia, the closely related Protococcales), but form permanent cell associations (Coenobia). In the genus Pediastrum, which includes many freshwater species, the social cells are always arranged in an elegantly shaped flat disc in a single layer. Within the green cell contents, there is always a shiny protein crystal (pyrenoid) as well as several small cell nuclei (here colored reddish). Reproduction usually takes place by zoospores, which are formed in a fixed number (4, 8, 16, 32) in a cell; then the cell wall opens at one point, and a gelatinous vesicle emerges from this birth slit of the mother cell, into which the mobile daughter cells pass (Fig. 8); already inside the vesicle, the latter organize themselves into a new disc. In most species, the disc is composed of 8 or 16 cells, more rarely 4, 32 or 64. The border cells are usually distinguished from the central cells by the formation of lobes, teeth or spines, which are differently formed depending on the species.

Species present on the naturalist board of Social Algae - Pediastrum :

• Pediastrum tetras
• Pediastrum patula
• Pediastrum granulatum
• Pediastrum octonum
• Pediastrum cruciatum
• Pediastrum selenaea
• Pediastrum pertusum
• Pediastrum elegans
• Pediastrum lunatum
• Pediastrum furcatum
• Pediastrum braunii
• Pediastrum ellipticum
• Pediastrum darwinii
• Pediastrum trochiscus
• Pediastrum solare