Fern

**1. Fern Characteristics and Taxonomy:**
– Ferns are vascular plants that reproduce via spores.
– They have complex leaves called megaphylls.
– Ferns first appeared in the fossil record about 360 million years ago.
– Ferns are herbaceous perennials and most lack woody growth.
– Ferns are classified as Polypodiopsida or Polypodiophyta.
– Carl Linnaeus recognized 15 genera of ferns.

**2. Fern Reproduction and Life Cycle:**
– Ferns reproduce by spores and do not have flowers or seeds.
– Ferns have an alternation of generations life cycle with diploid sporophytic and haploid gametophytic phases.
– The sporophyte has varying paired chromosomes, while the gametophyte has unpaired chromosomes.
– A diploid sporophyte produces haploid spores through meiosis.
– The spore develops into a free-living haploid gametophyte through mitosis.

**3. Fern Distribution, Habitat, and Ecology:**
– Ferns are widespread, with the greatest diversity in tropical rainforests.
– New Zealand has about 230 fern species.
– Ferns are specialists in marginal habitats and can thrive where flowering plants struggle.
– Some ferns are serious weed species, forming large colonies.
– Epiphytic ferns host a diverse range of invertebrates.

**4. Importance and Uses of Ferns:**
– Ferns are used for food, medicine, and as ornamental plants.
– They can remediate contaminated soil and act as biofertilizers.
– Certain fern species can remove pollutants from the atmosphere.
– Some ferns like bracken and water fern are significant weeds worldwide.
– Ferns like Azolla are used as biological fertilizers in rice paddies.

**5. Evolution, Classification Controversies, and Cultural Significance:**
– Ferns first appeared around 390 million years ago.
– Ferns evolved to cope with low-light conditions under angiosperm canopies.
– Classification of ferns is controversial, with differing viewpoints on taxonomy.
– Ferns have cultural significance, such as being the national emblem of New Zealand.
– Pteridology is the study of ferns and pteridophytes.

Fern (Wikipedia)

This article is about a group of plants. For other uses, see Fern (disambiguation) and Ferns (disambiguation).

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The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients and in having life cycles in which the branched sporophyte is the dominant phase.

Ferns Temporal range: Middle Devonian—Present PreꞒ Ꞓ O S D C P T J K Pg N
Psilotales Equisetales Marattiales Osmundales Hymenophyllales Gleicheniales Cyatheales Polypodiales
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Division:	Polypodiophyta
Class:	Polypodiopsida Cronquist, Takht. & W.Zimm.
Subclasses
†Stauropterididae †Zygopterididae Equisetidae Marattiidae Ophioglossidae Polypodiidae
Synonyms
Filicatae Kubitski 1990 Filices Filicophyta Endlicher 1836 Monilophyta Cantino & Donoghue 2007 Pteridopsida Ritgen 1828

Ferns have complex leaves called megaphylls, that are more complex than the microphylls of clubmosses. Most ferns are leptosporangiate ferns. They produce coiled fiddleheads that uncoil and expand into fronds. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate (Polypodiidae) and eusporangiate ferns, the latter group including horsetails, whisk ferns, marattioid ferns, and ophioglossoid ferns.

Ferns first appear in the fossil record about 360 million years ago in the late Devonian period, but Polypodiales, the group that makes up 80% of living fern diversity, did not appear and diversify until the Cretaceous, contemporaneous with the rise of flowering plants that came to dominate the world's flora.

Ferns are not of major economic importance, but some are used for food, medicine, as biofertilizer, as ornamental plants, and for remediating contaminated soil. They have been the subject of research for their ability to remove some chemical pollutants from the atmosphere. Some fern species, such as bracken (Pteridium aquilinum) and water fern (Azolla filiculoides), are significant weeds worldwide. Some fern genera, such as Azolla, can fix nitrogen and make a significant input to the nitrogen nutrition of rice paddies. They also play certain roles in folklore.