''Drosera filiformis'', commonly known as the thread-leaved sundew, is a small,

insectivorous A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant which eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores we ...

, rosette-forming 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 ...

herb Herbs are a widely distributed and widespread group of plants, excluding vegetables, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal purposes, or for fragrances. Culinary use typically distingu ...

. A species of sundew, it is unusual within its genus in that the long, erect, filiform (thread-like) leaves of this plant unroll in spirals – an arrangement similar to the circinate vernation seen in

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 ...

Distribution and habitat

''D. filiformis'' occurs naturally in both

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

and the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

; its natural range extends down the eastern seaboard of

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 ...

from south western

Nova Scotia Nova Scotia is a Provinces and territories of Canada, province of Canada, located on its east coast. It is one of the three Maritime Canada, Maritime provinces and Population of Canada by province and territory, most populous province in Atlan ...

in the north down through

New England New England is a region consisting of six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the ...

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

in the south. Its disjunct distribution on the Atlantic Coast reflects the prehistoric land connection between Nova Scotia and

Cape Cod, Massachusetts Cape Cod is a peninsula extending into the Atlantic Ocean from the southeastern corner of Massachusetts, in the northeastern United States. Its historic, maritime character and ample beaches attract heavy tourism during the summer months. The ...

, which formed an ancient extension of the Atlantic Plain region that likely persisted well into the current interglacial period as an island chain. ''D. filiformis'' is also found on the Gulf Coast from Florida to

Louisiana Louisiana ( ; ; ) is a state in the Deep South and South Central regions of the United States. It borders Texas to the west, Arkansas to the north, and Mississippi to the east. Of the 50 U.S. states, it ranks 31st in area and 25 ...

, although the Gulf Coast population may represent '' Drosera tracyi''.

Cultivation

''D. filiformis'' is frequently cultivated, with a few registered cultivars, such as ''D. filiformis'' var. ''filiformis'' (also known as ''D. filiformis'' typical), ''D. filiformis'' × 'California Sunset' (a hybrid between ''D. filiformis'' var. ''filiformis''.) All of these cultivars are grown with similar conditions as most other ''Drosera'' species: mineral-poor soil and distilled,

reverse osmosis Reverse osmosis (RO) is a water purification process that uses a partially permeable membrane, semi-permeable membrane to separate water molecules from other substances. RO applies pressure to overcome osmotic pressure that favors even distribu ...

, or collected rain water. ''D. filiformis'' require a winter dormancy for long-term survival, forming hibernacula in the winter.

Conservation

''D. filiformis'' is a Schedule 1–listed endangered species of Canada under the

Species at Risk Act The ''Species at Risk Act'' (, SARA) is a piece of Canadian federal legislation which became law in Canada on December 12, 2002. It is designed to meet one of Canada's key commitments under the International Convention on Biological Diversity. T ...

. It is considered range-wide to be of "least concern" according to the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

. Threats include development,

peat mining Peat is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. ''Sphagnum'' moss, also called peat moss, is one of the most common components in pea ...

and competition from shrubs.

Infraspecific taxa

*''Drosera filiformis'' f. ''tracyi'' (Macf. ''ex'' Diels) Macf. (1914) *''Drosera filiformis'' var. ''tracyi'' (Macf. ''ex'' Diels) Diels (1906) *''Drosera filiformis'' var. ''typica'' Winne (1944) ''nom.illeg.''

References

{{Taxonbar, from=Q366314 Carnivorous plants of North America filiformis Flora of the Eastern United States Flora of Canada Plants described in 1808 Taxa named by Constantine Samuel Rafinesque