Polypodiales | |
---|---|
Polypodium californicum | |
Scientific classification | |
Kingdom: | Plantae |
Subkingdom: | Embryophyta |
(unranked): | Tracheophyta |
(unranked): | euphyllophytes |
Class: | Polypodiopsida |
Subclass: | Polypodiidae |
Order: | Polypodiales |
Suborders | |
6. See text |
6. See text
The order Polypodiales encompasses the major lineages of polypod ferns, which comprise more than 80% of today's fern species. They are found in many parts of the world including tropical, semitropical and temperate areas. The characteristics of this group include: sporangia with a vertical annulus interrupted by the stalk and stomium; indusia laterally or centrally attached (or lost); gametophytes green, chordate, and surficial.
Historically, the ferns have undergone many different classifications (see review by Christenhusz and Chase, 2014). Smith et al. (2006) carried out the first higher-level pteridophyte classification published in the molecular phylogenetic era. Smith referred to the ferns as monilophytes, dividing them into four groups. The vast majority of ferns were placed in the Polypodiopsida, and that arrangement has persisted through all subsequent systems, despite some changes in nomenclature. Polypodiopsida is used in the strict sense (sensu stricto) by Smith et al. since it later came to be applied to all ferns (sensu lato), while this large group became known as Polypodiidae. This group is also informally known as the leptosporangiate ferns, while the remaining three groups (subclasses) ar referred to as eusporangiate ferns. The Polypodiidae have been divided into seven orders since that study, the largest of which is Polypodiales. The phylogenetic relationship between the orders of Polypodiidae is shown in this cladogram.