Figure 1. Glaucocystophytes, morphology and size of cells and colonies. (a) C. paradoxa (9–16/7); (b) P. cyanea (N, but cyanelle (?) diameter about 5 m); (c1) G. nostochinearum var. geitleri (more broad than long: 19–30/30–50); (c2) G. nostochinearum var. incrassata normal cell (16/23), developing eight-autospore mother cell (23/29) (carmine acetic acid staining of nuclei); (c3) colony with six cells developed from an originally four-autospore mother cell (two of the four autospores have already divided again, now by normal mitotic bipartition); (d) G. wittrockiana: (d1) zoospore (N), (d2) vegetative cell, and (d3) colony with eight vegetative cells (11–32), in the inferior cell series the pseudocilia have been removed; (e) C. gloeocystis f. dispersa: (e1) zoospore (32–44/21–23) and (e2) colony with four vegetative cells (24–36/17–22); the other four sister cells were split off. (Drawn after micrographs of Kies, 1976, 1989 (d, e), Hanf and Schenk (a, c1, c3), Schnepf et al., (1966) (c2), and a sketch of Pascher, (1929) (b)). Numbers in parentheses are size limits (m) of cells in relation to the cell axis: left numbers length/right numbers width (if one number then average value; N, size not given); a, anterior flagellum; b, mucilage body; c, centroplasm; f, flagellar groove; l, lipid droplet, m, muroplast or cyanelle; m’, muroplast digested; n, nucleus; p, pseudocilium; s, starch grain; v, pulsating vacuole; w, cell wall (of mother cell); w1, w2, w3, cell wall of first, second and third generation.

Figure 2. Phylogenetic dendrograms. (a) Phylogeny of eukaryotes based on small subunit ribosomal RNA (SS-rRNA) sequence comparison, inferred by the maximum-likelihood method and rooted within the branch leading to Dictyostelium discoideum. The branch of glaucocystophytes represents the cluster of C. paradoxa, G. nostochinearum and G. wittrockiana, that of nucleomorphs contains the SS-rRNA sequences of chlorarachniophytan and cryptophytan nucleomorphs. The dotted lines each represent a cluster and give the limits between shortest and longest branch lengths of the combined homologue sequences (drawn and greatly simplified after Bhattacharya et al., 1995). (b) Plastid phylogeny deduced from about 11 000 amino acid positions of 45 orthologous proteins common to the investigated plastomes and to the genome of the cyanobacterium Synechocystis PCC 6803, used as root (drawn and altered after Martin et al., 1998). The genomic levels of both the organismic (a) and the organellar (b) seem to support the idea that the phylogenetic branching position of glaucocystophytes is located near the evolutionary base of all eukaryotic photoautotrophic organisms.