1922 Journal of Heredity  
THE BOSTON FERN REPRODUCES ONLY BY RUNNERS FIGURE 6 . Many species of ferns reproduce both by runners and by spores, but the Boston fern produces no spores, so that new varieties arise only as bud variations of the stolons or runners, which are given off in association with each leaf. The stolons bear the roots which supply the main stem and leaves with food, and at intervals they also give rise to new plants by budding. The plant shown is a type of sword fern collected in Porto Rico for the
more » ... rto Rico for the New York Botanical Garden. Downloaded from https://academic.oup.com/jhered/article-abstract/13/6/255/766923 by Durham University user on 13 March 2018 WILD SWORD FERNS FROM FLORIDA FIGURE 7. The smaller one is the typical form, while the other is a variant. The larger plant differs from the normal in other respects than size. The pinnae are set farther apart and are all curved backward with hooking tips. The fronds are also somewhat more curved, but are not so graceful as those of a Boston fern grown under similar conditions. The sword fern is the progenitor of the Boston fern, which appeared as a bud sport.
doi:10.1093/oxfordjournals.jhered.a102218 fatcat:ltbql43x5zhhllwntxpubotxme