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47-545: Arnica / ˈ ɑːr n ɪ k ə / is a genus of perennial , herbaceous plants in the sunflower family ( Asteraceae ). The genus name Arnica may be derived from the Greek arni , "lamb", in reference to the plants' soft, hairy leaves. Arnica is also known by the names mountain tobacco and, confusingly, leopard's bane and wolfsbane —two names that it shares with the entirely unrelated genus Aconitum . This circumboreal and montane (subalpine) genus occurs mostly in

94-443: A century plant can live for 80 years and grow 30 meters tall before flowering and dying. However, most perennials are polycarpic (or iteroparous ), flowering over many seasons in their lifetime. Perennials invest more resources than annuals into roots, crowns, and other structures that allow them to live from one year to the next. They often have a competitive advantage because they can commence their growth and leaf out earlier in

141-940: A photolyase and the other, a protein involved in nucleotide excision repair ). Perennials that are cultivated include: woody plants like fruit trees grown for their edible fruits; shrubs and trees grown as landscaping ornamentals ; herbaceous food crops like asparagus , rhubarb , strawberries ; and subtropical plants not hardy in colder areas such as tomatoes , eggplant , and coleus (which are treated as annuals in colder areas). Perennials also include plants grown for their flowering and other ornamental value including bulbs (like tulips, narcissus, and gladiolus); lawn grass, and other groundcovers , (such as periwinkle and Dichondra ). Each type of plant must be separated differently; for example, plants with fibrous root systems like daylilies, Siberian iris, or grasses can be pried apart with two garden forks inserted back to back, or cut by knives. However, plants such as bearded irises have

188-734: A class Equisetopsida ( Embryophyta ) encompassing all land plants. This is referred to as Equisetopsida sensu lato to distinguish it from the narrower use to refer to horsetails alone, Equisetopsida sensu stricto . They placed the lycopods into subclass Lycopodiidae and the ferns, keeping the term monilophytes, into five subclasses, Equisetidae, Ophioglossidae, Psilotidae, Marattiidae and Polypodiidae, by dividing Smith's Psilotopsida into its two orders and elevating them to subclass (Ophioglossidae and Psilotidae). Christenhusz et al. (2011) followed this use of subclasses but recombined Smith's Psilotopsida as Ophioglossidae, giving four subclasses of ferns again. Christenhusz and Chase (2014) developed

235-429: A deep-rooted, erect stem that is usually unbranched. Their downy opposite leaves are borne towards the apex of the stem. The ovoid, leathery basal leaves are arranged in a rosette. They show large yellow or orange flowers , 6–8 cm (2–3 in) wide with 10–15 cm (4–6 in) long ray florets and numerous disc florets. The phyllaries (a bract under the flowerhead) has long spreading hairs. Each phyllary

282-628: A few species (e.g., Cyathea brownii on Norfolk Island and Cyathea medullaris in New Zealand ). Roots are underground non-photosynthetic structures that take up water and nutrients from soil . They are always fibrous and are structurally very similar to the roots of seed plants. As in all vascular plants , the sporophyte is the dominant phase or generation in the life cycle . The gametophytes of ferns, however, are very different from those of seed plants. They are free-living and resemble liverworts , whereas those of seed plants develop within

329-483: A new classification of ferns and lycopods. They used the term Polypodiophyta for the ferns, subdivided like Smith et al. into four groups (shown with equivalents in the Smith system), with 21 families, approximately 212 genera and 10,535 species; This was a considerable reduction in the number of families from the 37 in the system of Smith et al., since the approach was more that of lumping rather than splitting. For instance

376-462: A protective coating called an indusium . The arrangement of the sporangia is important in classification. In monomorphic ferns, the fertile and sterile leaves look morphologically the same, and both are able to photosynthesize. In hemidimorphic ferns, just a portion of the fertile leaf is different from the sterile leaves. In dimorphic (holomorphic) ferns, the two types of leaves are morphologically distinct . The fertile leaves are much narrower than

423-463: A root system of rhizomes; these root systems should be planted with the top of the rhizome just above ground level, with leaves from the following year showing. The point of dividing perennials is to increase the amount of a single breed of plant in your garden. In the United States more than 900 million dollars worth of potted herbaceous perennial plants were sold in 2019. Although most of humanity

470-430: A short-lived structure anchored to the ground by rhizoids called gametophyte which produce gametes. When a mature fertile frond bears sori, and spores are released, the spores will settle on the soil and send out rhizoids , while it develops into a prothallus . The prothallus bears spherical antheridia ( s.g. antheridium ) which produce antherozoids (male gametophytes) and archegonia ( s.g. archegonium ) which release

517-812: A significant input to the nitrogen nutrition of rice paddies . They also play certain roles in folklore. Extant ferns are herbaceous perennials and most lack woody growth. When woody growth is present, it is found in the stem. Their foliage may be deciduous or evergreen , and some are semi-evergreen depending on the climate. Like the sporophytes of seed plants, those of ferns consist of stems, leaves and roots. Ferns differ from spermatophytes in that they reproduce by spores rather than having flowers and producing seeds. However, they also differ from spore-producing bryophytes in that, like seed plants, they are polysporangiophytes , their sporophytes branching and producing many sporangia. Also unlike bryophytes, fern sporophytes are free-living and only briefly dependent on

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564-568: A single oosphere . The antherozoid swims up the archegonium and fertilize the oosphere, resulting in a zygote, which will grow into a separate sporophyte, while the gametophyte shortly persists as a free-living plant. Carl Linnaeus (1753) originally recognized 15 genera of ferns and fern allies, classifying them in class Cryptogamia in two groups, Filices (e.g. Polypodium ) and Musci (mosses). By 1806 this had increased to 38 genera, and has progressively increased since ( see Schuettpelz et al (2018) ). Ferns were traditionally classified in

611-479: A very few (e.g. Zostera ) occurring in shallow sea water. Herbaceous perennial plants are particularly dominant in conditions too fire-prone for trees and shrubs, e.g., most plants on prairies and steppes are perennials; they are also dominant on tundra too cold for tree growth. Nearly all forest plants are perennials, including trees and shrubs. Perennial plants are usually better long-term competitors, especially under stable, resource-poor conditions. This

658-493: Is polyphyletic , the term fern allies should be abandoned, except in a historical context. More recent genetic studies demonstrated that the Lycopodiophyta are more distantly related to other vascular plants , having radiated evolutionarily at the base of the vascular plant clade , while both the whisk ferns and horsetails are as closely related to leptosporangiate ferns as the ophioglossoid ferns and Marattiaceae . In fact,

705-400: Is associated with a ray floret. Species of Arnica , with an involucre (a circle of bracts arranged surrounding the flower head) arranged in two rows, have only their outer phyllaries associated with ray florets. The flowers have a slight aromatic smell. The seedlike fruit has a pappus of plumose, white or pale tan bristles. The entire plant has a strong and distinct pine-sage odor when

752-783: Is due to the development of larger root systems which can access water and soil nutrients deeper in the soil and to earlier emergence in the spring. Annual plants have an advantage in disturbed environments because of their faster growth and reproduction rates. Each section contains a short list of species related to that topic, these are an example as the true lists would fill several books. Perennials grown for their decorative flowers include very many species and types. Some examples include: The majority of fruit bearing plants are perennial even in temperate climates. Examples include: Many herbs are perennial, including these examples: Many vegetable plants can grow as perennials in tropical climates, but die in cold weather. Examples of some of

799-483: Is fed by the re-sowing of the seeds of annual grain crops, (either naturally or by the manual efforts of humans), perennial crops provide numerous benefits. Perennial plants often have deep, extensive root systems which can hold soil to prevent erosion , capture dissolved nitrogen before it can contaminate ground and surface water, and out-compete weeds (reducing the need for herbicides ). These potential benefits of perennials have resulted in new attempts to increase

846-578: Is intermediate between the eusporangiate ferns and the leptosporangiate ferns. Rai and Graham (2010) broadly supported the primary groups, but queried their relationships, concluding that "at present perhaps the best that can be said about all relationships among the major lineages of monilophytes in current studies is that we do not understand them very well". Grewe et al. (2013) confirmed the inclusion of horsetails within ferns sensu lato , but also suggested that uncertainties remained in their precise placement. Other classifications have raised Ophioglossales to

893-429: Is too cold or dry. In many parts of the world, seasonality is expressed as wet and dry periods rather than warm and cold periods, and deciduous perennials lose their leaves in the dry season. Some perennial plants are protected from wildfires because they have underground roots that produce adventitious shoots, bulbs, crowns , or stems ; other perennials like trees and shrubs may have thick cork layers that protect

940-640: 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

987-475: The astronomical symbol for the planet Jupiter . Perennial plants can be short-lived (only a few years) or long-lived. They include a wide assortment of plant groups from non-flowering plants like ferns and liverworts to highly diverse flowering plants like orchids , grasses , and woody plants . Plants that flower and fruit only once and then die are termed monocarpic or semelparous ; these species may live for many years before they flower. For example,

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1034-472: The class Filices, and later in a Division of the Plant Kingdom named Pteridophyta or Filicophyta. Pteridophyta is no longer recognised as a valid taxon because it is paraphyletic . The ferns are also referred to as Polypodiophyta or, when treated as a subdivision of Tracheophyta (vascular plants), Polypodiopsida, although this name sometimes only refers to leptosporangiate ferns. Traditionally, all of

1081-446: The advantage of generating larger seedlings that can better compete with other plants. Perennials also produce seeds over many years. An important aspect of cold acclimation is overexpression of DNA repair genes. In Thinopyrum intermedium a perennial relative of common wheat Triticum aestivum , conditions of freezing stress were shown to be associated with large increases in expression of two DNA repair genes (one gene product

1128-478: The branched sporophyte is the dominant phase. 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

1175-510: The dormancy period is over and new growth begins. In climates that are warm all year long, perennials may grow continuously. Annuals which complete their life cycle in one growing season, in contrast with perennials, produce seeds as the next generation and die; the seeds may survive cold or dry periods or germinate soon after dispersal depending on the climate. Some perennials retain their foliage year-round; these are evergreen perennials. Deciduous perennials shed all their leaves part of

1222-431: The fronds are branched more than once, it can also be a combination of the pinnatifid are pinnate shapes. If the leaf blades are divided twice, the plant has bipinnate fronds, and tripinnate fronds if they branch three times, and all the way to tetra- and pentapinnate fronds. In tree ferns, the main stalk that connects the leaf to the stem (known as the stipe), often has multiple leaflets. The leafy structures that grow from

1269-541: The growing season, and can grow taller than annuals. In doing so they can better compete for space and collect more light. Perennials typically grow structures that allow them to adapt to living from one year to the next through a form of vegetative reproduction rather than seeding. These structures include bulbs , tubers , woody crowns, rhizomes , turions , woody stems, or crowns which allows them to survive periods of dormancy over cold or dry seasons; these structures typically store carbohydrates which are used once

1316-620: The hormones produced due to environmental situations (i.e., seasons), reproduction, and stage of development to begin and halt the ability to grow or flower. There is also a distinction between the ability to grow and the actual task of growth. For example, most trees regain the ability to grow during winter but do not initiate physical growth until the spring and summer months. The start of dormancy can be seen in perennial plants through withering flowers, loss of leaves on trees, and halting of reproduction in both flowering and budding plants. Perennial species may produce relatively large seeds that have

1363-488: The inclusion of Equisetaceae in the ferns, notably relating to the construction of their sperm and peculiarities of their roots. The leptosporangiate ferns are sometimes called "true ferns". This group includes most plants familiarly known as ferns. Modern research supports older ideas based on morphology that the Osmundaceae diverged early in the evolutionary history of the leptosporangiate ferns; in certain ways this family

1410-492: The leaves of mature plants are rubbed or bruised. The species Arnica montana , native to Europe , has long been used medicinally, but the effectiveness of this use has not been substantiated. Arnica montana contains the toxin helenalin , which can be poisonous if large amounts of the plant are eaten, and contact with the plant can also cause skin irritation. Accepted species: Perennial plant Perennials (especially small flowering plants ) that grow and bloom over

1457-446: The leptosporangiate ( Polypodiidae ) and eusporangiate ferns , the latter group including horsetails , whisk ferns , marattioid ferns , and ophioglossoid ferns . The fern crown group , consisting of the leptosporangiates and eusporangiates, is estimated to have originated in the late Silurian period 423.2 million years ago, but Polypodiales , the group that makes up 80% of living fern diversity, did not appear and diversify until

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1504-467: The leptosporangiate ferns. The Marattiaceae are a primitive group of tropical ferns with large, fleshy rhizomes and are now thought to be a sibling taxon to the leptosporangiate ferns. Several other groups of species were considered fern allies: the clubmosses , spikemosses , and quillworts in Lycopodiophyta ; the whisk ferns of Psilotaceae ; and the horsetails of Equisetaceae . Since this grouping

1551-555: The maternal gametophyte . The green , photosynthetic part of the plant is technically a megaphyll and in ferns, it is often called a frond . New leaves typically expand by the unrolling of a tight spiral called a crozier or fiddlehead into fronds . This uncurling of the leaf is termed circinate vernation . Leaves are divided into two types: sporophylls and tropophylls. Sporophylls produce spores; tropophylls do not. Fern spores are borne in sporangia which are usually clustered to form sori . The sporangia may be covered with

1598-495: The more completely perennial vegetables are: Many aquatic plants are perennial even though many do not have woody tissue. Examples include: Fern 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

1645-430: The rank of a fifth class, separating the whisk ferns and ophioglossoid ferns. The ferns are related to other groups as shown in the following cladogram: Lycophytes [REDACTED] Ferns [REDACTED] Gymnosperms [REDACTED] Angiosperms [REDACTED] The classification of Smith et al. in 2006 treated ferns as four classes: In addition they defined 11 orders and 37 families. That system

1692-465: The seed yield of perennial species, which could result in the creation of new perennial grain crops. Some examples of new perennial crops being developed are perennial rice and intermediate wheatgrass . A perennial rice developed in 2018, was reported in 2023, to have provided a similar yield to replanted annual rice when evaluated over eight consecutive harvests. Perennial plants dominate many natural ecosystems on land and in fresh water, with only

1739-476: The spore producing vascular plants were informally denominated the pteridophytes , rendering the term synonymous with ferns and fern allies . This can be confusing because members of the division Pteridophyta were also denominated pteridophytes ( sensu stricto ). Traditionally, three discrete groups have been denominated ferns: two groups of eusporangiate ferns, the families Ophioglossaceae ( adder's tongues , moonworts , and grape ferns) and Marattiaceae ; and

1786-417: The spore wall and are dependent on the parent sporophyte for their nutrition. A fern gametophyte typically consists of: The lifecycle of a fern involves two stages, as in club mosses and horsetails . In stage one, the spores are produced by sporophytes in sporangia , which are clustered together in sori ( s.g. sorus ), developing on the underside of fertile fronds. In stage two, the spores germinate into

1833-668: The spring and summer, die back every autumn and winter, and then return in the spring from their rootstock or other overwintering structure, are known as herbaceous perennials . However, depending on the rigours of the local climate (temperature, moisture, organic content in the soil, microorganisms), a plant that is a perennial in its native habitat, may be treated by a gardener as an annual and planted out every year, from seed, from cuttings, or from divisions. Tomato vines, for example, live several years in their natural tropical/ subtropical habitat but are grown as annuals in temperate regions because their above-ground biomass does not survive

1880-431: The stems. Herbaceous perennials from temperate and alpine regions of the world can tolerate the cold during winter. Perennial plants may remain dormant for long periods and then recommence growth and reproduction when the environment is more suitable, while most annual plants complete their life cycle during one growing period, and biennials have two growing periods. The meristem of perennial plants communicates with

1927-490: The sterile leaves, and may have no green tissue at all, as in the Blechnaceae and Lomariopsidaceae . The anatomy of fern leaves can be anywhere from simple to highly divided, or even indeterminate (e.g. Gleicheniaceae , Lygodiaceae ). The divided forms are pinnate , where the leaf segments are completely separated from one other, or pinnatifid (partially pinnate), where the leaf segments are still partially connected. When

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1974-463: The stipe are known as pinnae and are often again divided into smaller pinnules. Fern stems are often loosely called rhizomes , even though they grow underground only in some of the species. Epiphytic species and many of the terrestrial ones have above-ground creeping stolons (e.g., Polypodiaceae ), and many groups have above-ground erect semi-woody trunks (e.g., Cyatheaceae , the scaly tree ferns). These can reach up to 20 meters (66 ft) tall in

2021-458: The temperate regions of western North America , with a few species native to the Arctic regions of northern Eurasia and North America . Arnica species are used as food plants by the larvae of some Lepidoptera species, including Bucculatrix arnicella . Arnica was previously classified in the tribe Senecioneae because it has a flower or pappus of fine bristles. Arnica plants have

2068-477: The whisk ferns and ophioglossoid ferns are demonstrably a clade , and the horsetails and Marattiaceae are arguably another clade. Smith et al. (2006) carried out the first higher-level pteridophyte classification published in the molecular phylogenetic era, and considered the ferns as monilophytes, as follows: Molecular data, which remain poorly constrained for many parts of the plants' phylogeny, have been supplemented by morphological observations supporting

2115-405: The winter. There is also a class of evergreen perennials which lack woody stems, such as Bergenia which retain a mantle of leaves throughout the year. An intermediate class of plants is known as subshrubs , which retain a vestigial woody structure in winter, e.g. Penstemon . The symbol for a perennial plant, based on Species Plantarum by Linnaeus , is [REDACTED] , which is also

2162-439: The year. Deciduous perennials include herbaceous and woody plants; herbaceous plants have stems that lack hard, fibrous growth, while woody plants have stems with buds that survive above ground during dormancy. Some perennials are semi-deciduous, meaning they lose some of their leaves in either winter or summer. Deciduous perennials shed their leaves when growing conditions are no longer suitable for photosynthesis, such as when it

2209-844: Was a consensus of a number of studies, and was further refined. The phylogenetic relationships are shown in the following cladogram (to the level of orders). This division into four major clades was then confirmed using morphology alone. Lycopodiophytes (club mosses, spike mosses, quillworts) Spermatophytes (seed plants) Equisetales (horsetails) [REDACTED] Ophioglossales (grapeferns etc.) Psilotales (whisk ferns) [REDACTED] Marattiales [REDACTED] Osmundales [REDACTED] Hymenophyllales (filmy ferns) [REDACTED] Gleicheniales [REDACTED] Schizaeales Salviniales (heterosporous) Cyatheales (tree ferns) [REDACTED] Polypodiales [REDACTED] Subsequently, Chase and Reveal considered both lycopods and ferns as subclasses of

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