Cryptogamie, Algologie
31 (2) - Pages 221-228The morphology and morphometry of Chara globularis oospores were studied in a population collected from Lake Wielkie Pocice (NW Poland) at two depths. The longest polar axis and the largest equatorial diameter of the oospores, number of ridges, and width of fossa at the equator, as well as the ISI (length:width × 100) and ANI (distance between the apical pole and the equator:width × 100) ratios, were measured and calculated. The wall structure was examined using scanning electron microscopy. Oospores were prolate and ovoidal or ellipsoidal in outline. The wall was granular with distinctly marked ridges. Oospores were 550-783 m long and 283-433 μm wide. Values of the ISI index were between 146 to 245. There were 12-15 ridges on the oospore surface and the width of fossa varied from 33 to 58 μm. Variation coefficients were 5 for the number of ridges and 18 for the ANI index. Statistically significant differences in terms of length, ISI index and number of ridges between oospores from different depths were found. The largest and most prolate oospores occurred on individuals growing at a depth of 1.5 m. We hypothesize that this is related to increased light availability at that depth.