<P> A gemma (plural gemmae) is a single cell, or a mass of cells, or a modified bud of tissue, that detaches from the parent and develops into a new individual . This type of asexual reproduction is referred to as fragmentation . It is a means of asexual propagation in plants . These structures are commonly found in fungi, algae, liverworts and mosses, but also in some flowering plants such as pygmy sundews and some species of butterworts . Vascular plants have many other methods of asexual reproduction including bulbils and turions . </P> <P> The production of gemmae is a widespread means of asexual reproduction in both liverworts and mosses . In liverworts such as Marchantia, the flattened plant body or thallus is a haploid gametophyte with gemma cups scattered about its upper surface . The gemma cups are cup - like structures containing gemmae . The gemmae are small discs of haploid tissue, and they directly give rise to new gametophytes . They are dispersed from gemma cups by rainfall . </P> <P> The gemmae are bilaterally symmetrical and are not differentiated into dorsal and ventral surfaces . The mature gemmae fall on the ground and if conditions are suitable their germination starts immediately . The surface of the gemma which comes in contact of the soil gives out many rhizoids . This surface eventually becomes the lower (ventral) surface of the thallus . Meanwhile, the apical cells present in the two lateral notches become active and form two thalli in opposite directions . </P>

The importance of gemma cups in marchantia sp
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