A DESCRIPTIVE AND ULTRASTRUCTURAL STUDY OF THE GREEN ALGA, CHLAMYDOMONAS DESMIDII SP. NOV. (VOLVOCALES. CHLAMYDOMONADACEAE) FROM ROCKY MOUNTAIN NATIONAL PARK LAKES ¹

Abstract

The green algal flagellate Chlamydomonas desmidii sp. nov., is described from several lakes in Rocky Mountain National Park, Colorado. The biflagellate cells generally have an hour‐glass shape. They possess a single chloroplast with two pyrenoids and a superficial stigma near the center of the cell. Numerous contractile vacuoles occur in the Peripheral cytoplasm and they are arranged in several rings around the nucleus in the constricted region of the cell. Ultrastructural studies verify these features and elaborate upon the structure of the cell.

Taxonomic revision of Chlamydomonas subg. Amphichloris (Volvocales, Chlorophyceae), with resurrection of the genus Dangeardinia and descriptions of Ixipapillifera gen. nov. and Rhysamphichloris gen. nov.

“…The vegetative cells of authentic strain of Cd. desmidii , UTEX 2733, have numerous contractile vacuoles in the middle region (Kugrens and Delivopoulos ), and this strains was clearly distinguished from the other strains having two apical contractile vacuoles. Other groups of strains, each having identical 18S r RNA sequences, were distinguished from each other by light (Figs.…”

“…; figs. 1–5, 7, 9 in Kugrens and Delivopoulos ). The Amp‐C clade was further characterized by its mitochondrial morphology (Figs.…”

“…; figs. 1–5, 7, 9 in Kugrens and Delivopoulos ). The surface appearance of the chloroplast is also a helpful diagnostic character, especially in distinguishing Rhysamphichloris (with its longitudinally ribbed surface; Figs.…”

“…, B and E; , F and G), while Dangeardinia have intermediate types of stigmata (circular, broad elliptic, or more irregular; Figs. B; , B, D, F; Kugrens and Delivopoulos ).…”

“…), despite 21 species having been recognized in the Chlamydomonas subg. Amphichloris by microscopic methods (Iyengar and Desikachary , Ettl , Kugrens and Delivopoulos ).…”