Plant reproductive morphology
![Close-up of a flower of Schlumbergera (Christmas or Holiday Cactus), showing part of the gynoecium (the stigma and part of the style is visible) and the stamens that surround it](/Images/godic/202502/14/Schlumbergera_04_ies4641.jpg")
![Dioicous gametophytes of the liverwort Marchantia polymorpha. In this species, gametes are produced on different plants on umbrella-shaped gametophores with different morphologies. The radiating arms of female gameteophores (left) protect archegonia that produce eggs. Male gametophores (right) are topped with antheridia that produce sperm.](/Images/godic/202502/14/Marchantia_polymorpha_gametophytes4641.jpg")
![Flower of Ranunculus glaberrimus](/Images/godic/202502/14/Ranunculus_glaberrimus_labelled4641.jpg")
![Alnus serrulata has unisexual flowers and is monoecious. Shown here: maturing male flower catkins on the right, last year's female catkins on the left.](/Images/godic/202502/14/Tagalder81394641.jpg")
Plant reproductive morphology is concerned with the physical form and structure (the morphology) of those parts of plants directly or indirectly concerned with sexual reproduction.
Among all living organisms, flowers, which are the reproductive structures of angiosperms, are the most varied physically and show a correspondingly great diversity in methods of reproduction. Plants that are not flowering plants (green algae, mosses, liverworts, hornworts, ferns and gymnosperms such as conifers) also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction. The breeding system, or how the sperm from one plant fertilizes the ovum of another, depends on the reproductive morphology, and is the single most important determinant of the genetic structure of nonclonal plant populations. Christian Konrad Sprengel (1793) studied the reproduction of flowering plants and for the first time it was understood that the pollination process involved both biotic and abiotic interactions. Charles Darwin's theories of natural selection utilized this work to build his theory of evolution, which includes analysis of the coevolution of flowers and their insect pollinators.