-Gracilaria is a red alga (Rhodophyta) genus. Carpogonium is the stationary female gametes in Gracilaria. It comprises the reproductive nucleus. A number of cells can be present, normally without chloroplasts. -Ectocarpus is a genus of filamentous brown algae, and biflagellate zoospores reproduce asexually. The pear-shaped form with two unequal laterally attached flagella is Biflagellate zoospores. In brown algae, this assists in asexual reproduction. -Marchantia, a group of liverworts, is a genus in the Marchantiaceae family of the order Marchantiales. The male gametes in Marchantia are called antherozoids and are structurally biflagellate. In response to changes in environmental moisture, an elater is a hygroscopic cell (or structure attached to a cell) that will therefore change shape. -Cycads are a group of gymnosperms that have top-shaped multiciliated male gametes (the largest male gamete) and contain one embryo and two cotyledons (dicotyledonous) in each mature seed of these plants. Cycas is a dioecious plant with one plant comprising both the male and the female. The male gametes are ciliated and flagellated. Both pollen tube formation and the presence of male gametes take part in this.