Why do horsetails often survive by vegetative reproduction instead of sexual reproduction?

While horsetails (Equisetum) do undergo a sexual life cycle involving the production of spores and the development of gametophytes, they rely heavily on vegetative reproduction for survival in nature. Although many gametophytes are initiated from spores each year, very few successfully produce new sporophytes.1

This reliance on vegetative reproduction is not because they lack a sexual phase, but rather because the transition from the sexual stage to the mature sporophyte is often unsuccessful in natural conditions. Consequently, horsetails persist and spread primarily through their underground stems, known as rhizomes, rather than depending on the regular completion of the sexual cycle to maintain their populations.1