Monoecy ( / m ə ˈ n iː s i / ; adj. monoecious / m ə ˈ n iː ʃ ə s / ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system comparable with gynomonoecy , andromonoecy and trimonoecy , and contrasted with dioecy where individual plants produce cones or flowers of only one sex and with bisexual or hermaphroditic plants in which male and female gametes are produced in the same flower.
10-573: Allagoptera is a monoecious genus of flowering plant in the palm family found in South America consisting of 5 accepted species . Compared to other genera within the Cocoseae Allagoptera is described as particularly specialized. The genus name is a Greek combination of "change" and "feather", describing the full leaf; it was formerly named Diplothemium . Allagoptera produces very short or acaulescent trunks and in cases where
20-453: A variety of habitats. Some thrive in sandy beaches and dunes, while others are found in woodlands; Allagoptera species are also common along sandstone hills and in the Cerrado vegetation. Monoecious Monoecy often co-occurs with anemophily , because it prevents self-pollination of individual flowers and reduces the probability of self-pollination between male and female flowers on
30-414: Is also considered to be a step in the evolutionary pathway from hermaphroditism towards dioecy. Some authors even argue monoecy and dioecy are related. But, there is also evidence that monoecy is a pathway from sequential hermaphroditism to dioecy. Gynomonoecy Gynomonoecy is defined as the presence of both female and hermaphrodite flowers on the same individual of a plant species. It
40-646: Is prevalent in Asteraceae but is poorly understood. It is a monomorphic sexual system comparable with monoecy , andromonoecy and trimonoecy . This sexual system occurs in about 2.8% of flowering plants. It is present in 3% of Silene species and 23 families of flowering plants, but is most common in the daisy family, Asteraceae . Of the approximately 23000 species in the Asteraceae about 200 are gynomonoecious. Gynomonoecy may be an intermediate evolutionary state between monoecy and hermaphroditism. It
50-554: Is prevalent in Euphorbiaceae . Dioecy is replaced by monoecy in polyploid populations of Mercurialis annua . Maize is monoecious since both pistillate (female) and stamenate (male) flowers occur on the same plant. The pistillate flowers are present on the ears of corn and the stamenate flowers are in the tassel at the top of the stalk. In the ovules of the pistillate flowers, diploid cells called megaspore mother cells undergo meiosis to produce haploid megaspores . In
60-731: The anthers of the stamenate flowers, diploid pollen mother cells undergo meiosis to produce pollen grains. Meiosis in maize requires gene product RAD51 , a protein employed in recombinational repair of DNA double-strand breaks . The evolution of monoecy has received little attention. Male and female flowers evolve from hermaphroditic flowers via andromonoecy or gynomonoecy . In amaranths monoecy may have evolved from hermaphroditism through various processes caused by male sterility genes and female fertility genes. Monoecy may be an intermediate state between hermaphroditism and dioecy. Evolution from dioecy to monoecy probably involves disruptive selection on floral sex ratios. Monoecy
70-450: The rachis each protruding into a different plane, creating a plumose leaf. The unusual spicate inflorescence emerges from within the leaf-crown carrying the pistilate flowers basally with the staminate flowers growing distally. The single-seeded fruit is yellow to brown, growing in crowded clusters. Palms in this genus are found in Brazil , Paraguay , Bolivia , and Argentina growing in
80-469: The same plant. Monoecy in angiosperms has been of interest for evolutionary biologists since Charles Darwin . Monoecious comes from the Greek words for one house. The term monoecy was first introduced in 1735 by Carl Linnaeus . Darwin noted that the flowers of monoecious species sometimes showed traces of the opposite sex function, suggesting that they evolved via hermaphroditism. Monoecious hemp
90-458: The trunk grows erect it often makes a downward turn leaving the crown below the trunk-base. The trunks in Allagoptera are among the few in the palm family which tend to bifurcate, producing multiple heads per unit. The pinnate leaves are gently arching to 2 m and are carried on long, slender petioles which are adaxially channeled. The single-fold leaflets are regularly or irregularly arranged on
100-438: Was first reported in 1929. Monoecy is most common in temperate climates and is often associated with inefficient pollinators or wind-pollinated plants. It may be beneficial to reducing pollen-stigma interference, thus increasing seed production. Around 10% of all seed plant species are monoecious. It is present in 7% of angiosperms . Most Cucurbitaceae are monoecious including most watermelon cultivars . It
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