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In seed plants, "monoecious" is used where flowers with anthers (microsporangia) and flowers with ovules (megasporangia) occur on the same sporophyte and "dioecious" where they occur on different sporophytes. These terms occasionally may be used instead of "monoicous" and "dioicous" to describe bryophyte gametophytes.
Meanwhile, "monoecious" and "dioecious" are used to describe diploid sexuality (sporophytic sexuality), and thus are used to describe tracheophytes (vascular plants) in which the sporophyte is the dominant generation.
The ancestral sexual system in bryophytes is unknown but it has been suggested monoicy and dioicy evolved several times. [11] It has also been suggested that dioicy is a plesiomorphic character for bryophytes. [4]: 71 In order for dioicy to evolve from monoicy it needs two mutations, a male sterility mutation and a female sterility mutation. [11]
(Many sources, including those concerned with bryophytes, use the term 'monoecious' for this situation and 'dioecious' for the opposite. [23] [24] Here 'monoecious' and 'dioecious' are used only for sporophytes.) The liverwort Pellia epiphylla has the gametophyte as the dominant generation. It is monoicous: the small reddish sperm-producing ...
Dioecy (/ d aɪ ˈ iː s i / dy-EE-see; [1] from Ancient Greek διοικία dioikía 'two households'; adj. dioecious, / d aɪ ˈ iː ʃ (i) ə s / dy-EE-sh(ee-)əs [2] [3]) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants).
Mosses can be either dioicous (compare dioecious in seed plants) or monoicous (compare monoecious). In dioicous mosses, male and female sex organs are borne on different gametophyte plants. In monoicous (also called autoicous) mosses, both are borne on the same plant.
Monoecy (/ m ə ˈ n iː s i /; adj. monoecious / m ə ˈ n iː ʃ ə s /) [1] is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. [2]
If separate staminate and carpellate flowers are always found on different plants, the species is described as dioecious. [6] A 1995 study found that about 6% of angiosperm species are dioecious, and that 7% of genera contain some dioecious species. [7] Members of the birch family are examples of monoecious plants with unisexual flowers.