Crossection of a Dandelion Compound Flower – Rüdiger Hartmann (2015)

Dandelion (Taraxacum officinale) is one of the most ubiquitous plants belonging to the family Asteraceae. The plant is native to Eurasia but has become naturalized to all temperate regions of the World introduced unintentionally by Humans. It’s compound flowers are self-pollinated and seeds are wind dispersed. In this short observation developmental biologist Dr. Rüdiger Hartmann of the University of Freiburg has done a wonderful job of showing the dynamics of the mature compound flowers (inflorescence) using timelapse videography in his studio in Lauterbach, Germany. He dissected the flowers in clearly labeled stages to show the mechanics of the familiar “blowballs” which is the final stage of the life cycle of this plant.

Dandelions are biennial plants. They live for two years. The first year is the vegetative stage during which they remain in rosette stage storing food in their taproot by photosynthesis. Rosettes can overwinter and continue to photosynthesize as long as the winter conditions are favorable. The second year is devoted to reproduction and all the food stored in the taproot is used to produce flowers and fruits. Mature fruits become seeds forming blowballs.

Plant world can be a little strange to us as animals. Flowers of the genus Taraxacum has a wide variety of reproduction modes. They can self-pollinate, cross-pollinate (even between two different species) or can be apomictic. Here in these videos the Taraxacum officinale seeds are produced through an asexual reproduction called apomixis. Seeds form directly from the maternal tissues of the ovule. It is a shortcut bypassing the biological processes of meiosis and fertilization. The animal version of this biological shortcut is called parthenogenesis. Female sharks can reproduce parthenogenically in the absence of males. Apomixis in plants was discovered after the observation that a solitary female plant of Alchornea ilicifolia (syn. Caelebogyne ilicifolia) from Australia suprisingly continued to form seeds when planted at Kew Botanical Gardens in England in 1840s. Apomixis make dandelions very successful since they don’t need pollinators like the other plants.

Löwenzahn, dandelion, diente de león (Taraxacum) from Rüdiger Hartmann on Vimeo.