Division 3 - Polypodiophyta
from Kingdom 1 - Plantae
Summary
Perennial (rarely annual) herbs, and some trees, with alternation of generations physiologically independent of each other at maturity. Sporophyte well developed, ordinarily differentiated into roots, stipe (stem) and frond (leaf), forming the phase of the life cycle that is usually seen. Stipe unbranched or more often dichotomously to monopodially branched, not producing dormant axillary buds, though the branches are sometimes axillary. Fronds mostly alternate, usually large and compound or cleft and with a branching vascular system, or sometimes much reduced. Sporangia borne on vegetative or modified fronds, often at the margins or on the underside, or sometimes in specialised sporocarps which represent modified frond segments or enlarged indusia. Sporophylls never aggregated into a terminal strobilus (cone). Gametophyte small, photosynthetic or less often mycorrhizal or depending on its stored food.
Contains 38 families. In this division species are being continually moved from one genus to another, but the large number of synonyms given will enable users to adopt whichever name they prefer.
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- Flora of Great Britain and Ireland , pp. 13 - 14Publisher: Cambridge University PressPrint publication year: 2018