''Osmunda spectabilis'', known as American royal fern, is a species of

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...

native to a large area of the New World, from the eastern half of Canada and the United States to Argentina.

Description

''Osmunda spectabilis'' is an easy fern to recognize in the New World flora. Although it closely resembles species '' O. regalis'', '' O. japonica'', and '' O. lancea'', only ''O. spectabilis'' is found growing naturally in the New World. The fronds of ''O. spectabilis'' can exceed 1 meter in length and are bipinnate. The pinnules are attached by a very narrow base. The plant produces separate sterile and fertile fronds. Fertile fronds are similar to the sterile fronds, in the lower and middle portions, but the top-most pinnae are fertile and they are much reduced and brown when mature in the early summer.

Distribution and habitat

American royal fern is most commonly found growing in wetter soils such as those found in wet forests, bogs, and along streams and lakes.

Taxonomy

''Osmunda spectabilis'' was formerly considered to be a variety of ''

Osmunda regalis ''Osmunda regalis'', or royal fern, is a species of deciduous fern, native to Europe, Africa and Asia, growing in woodland bogs and on the banks of streams. The species is sometimes known as flowering fern due to the appearance of its fertile fro ...

'' (''Osmunda regalis'' var. ''spectabilis''). Another variety, ''Osmunda spectabilis'' var. ''brasiliensis'', (formerly ''Osmunda regalis'' var. ''brasiliensis'') also exists in tropical regions of Central and South America, but it is only recognized by some authors. '' Osmunda angustifolia'', '' Osmunda bromeliifolia'', and all extinct ''

Osmunda ''Osmunda'' is a genus of primarily temperate-zone ferns of family Osmundaceae. Five to ten species have been listed for this genus. Description Completely dimorphic fronds or pinnae (hemidimorphic), green photosynthetic sterile fronds, and n ...

'' species are missing from this cladogram. The classification is based on the genetic analysis presented in "The Paraphyly of ''Osmunda'' is Confirmed by Phylogenetic Analyses of Seven Plastid Loci."Metzgar, Jordan S., Judith E. Skog, Elizabeth A. Zimmer, and Kathleen M. Pryer (2008). "The Paraphyly of ''Osmunda'' is Confirmed by Phylogenetic Analyses of Seven Plastid Loci." Systematic Botany https://sites.duke.edu/pryerlab/files/2017/12/metzgar-et-al-osmunda-2008.original.pdf

References

{{Taxonbar, from=Q7107257 Osmundales Ferns of the Americas Plants described in 1810