''Dryopteris expansa'', the alpine buckler fern, northern buckler-fern or spreading wood fern, is a species of
perennial
In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...
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 tissue ...
native to cool temperate and subarctic regions of the
Northern Hemisphere
The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...
, south at high altitudes in
mountain
A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...
s to
Spain
Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...
and
Greece
Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...
in southern
Europe
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
, to
Japan
Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...
in eastern
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...
, and to central
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
in
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
. It prefers cool, moist mixed or evergreen forests and rock crevices on alpine slopes, often growing on rotting logs and tree stumps and rocky slopes. It is characteristically riparian in nature, and is especially associated with stream banks.
Description
It has a short
rootstock
A rootstock is part of a plant, often an underground part, from which new above-ground growth can be produced. It could also be described as a stem with a well developed root system, to which a bud from another plant is grafted. It can refer to ...
. The leaves are with large, green lacy
frond
A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the lar ...
s typically . The petiole is usually about half the length of the leaf blade and brown scaled. The scales are black-ish in the middle. The leaf blade is triangular and sparsely
glandular
A gland is a cell or an organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. A gland may also function to remove unwanted substance ...
on the underside. The deltate fronds are bipinnate at the base, pinnate toward the apex. The
rhizome
In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...
is erect or ascending, often producing offshoots. Sori occur medially on the underside of the pinnae. Propagation is by
spore
In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...
s and vegetatively by division of the rhizome.
It is easily confused with the related '' Dryopteris dilatata'' (broad buckler fern), differing in the usually smaller fronds, and in the pale brown scales on the frond stem being more uniform in color, rarely having a dark central stripe. It also differs in
cytology
Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living an ...
in having 2n = 82
chromosome
A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...
s (164 in ''D. dilatata''). Leaves of ''D. expansa'' are very similar to those of '' D. arguta''.
Taxonomy
''Dryopteris expansa'' was given its first scientific description in 1825 by
Carl Borivoj Presl
Carl Borivoj Presl (; 17 February 1794 – 2 October 1852) was a Czech botanist.
Biography
Presl lived his entire life in Prague, and was a professor of botany at the University of Prague (1833–52). It was described in the book ''Reliquiae Haenkeanae'' as being described from a specimen collected at Nootka Sound. However, the type locations in that work cannot be relied upon due to mistakes made when the specimens were originally collected or during the long storage before being examined by Presl. The specimens were collected by Thaddäus Haenke during his long travels and sent back to Europe where they sat unregarded for at least 25 years until they were acquired by the Bohemian National Museum at Prague in 1821 and were finally examined in detail.
Names
The species name of this fern, ''expansa'', is from the
Latin
Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
''expando'', meaning "to spread out, spread apart, to expand". Other common names include northern wood fern, arching wood fern, spiny wood fern and crested wood fern.
The Finnish name is ''isoalvejuuri'' which directly translates to "large cestoda root" likely referring to its relations to use of other buckler ferns as worm expellent in traditional Finnish medicine especially Dryopteris filix-mas.
Uses
The root contains filicin, a substance that paralyses tapeworms and other internal
parasite
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...
s and has been used in herbal medicine as a worm expellent.