Isoetes lacustris
Encyclopedia
Isoetes lacustris is a boreal quillwort native on both sides of the northern Atlantic Ocean
. In Europe
, it is distributed from Poland
west to northeastern France
, throughout Scandinavia
, the west and north of the British Isles
, the Faroe Islands
and Iceland
. In the North America
, it occurs in the New England
states of Maine
, Vermont
, New Hampshire
and Massachusetts
, and in Canada
in in provinces of New Brunswick
and Nova Scotia
.
The lake quillwort has many long, narrow leaves
from 8–20 cm long and 0.5–2 mm broad, widening to 5 mm broad at the base. There is a sac that produces the spore
s at the bottom of each leaf base. The plant has a very short stem, called a corm
, where all the leaves and roots are attached close together. It does not have traditional roots, but instead some of its leaves are modified to act like roots. These pseudo-roots are called rhizomorphs, and are attached to the bottom end of corm. The upper leaves are green and found sprouting in a clump.
It is found on the stony or sandy bottoms of clear, usually slightly acid
ic ponds, typically in mountain
tarn
s, growing at 5–460 cm depth of water. They are perennial, with typically two flushes of new leaves each year, in spring and autumn.
Reproduction usually takes place during the late summer or early fall. The sacs at the bottom of leaves create two types of spores, female (megaspores, about 0.5 mm diameter) and male (microspores, a few micrometres in diameter). These spores represent the gametophyte phase of the life cycle.
This species is one of a few cultivated species of quillworts, either as an aquarium plant or as an educational resource.
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
. In Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, it is distributed from Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
west to northeastern France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, throughout Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
, the west and north of the British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...
, the Faroe Islands
Faroe Islands
The Faroe Islands are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland. The Faroe Islands are a self-governing territory within the Kingdom of Denmark, along with Denmark proper and Greenland...
and Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...
. In the North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, it occurs in the New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
states of Maine
Maine
Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...
, Vermont
Vermont
Vermont is a state in the New England region of the northeastern United States of America. The state ranks 43rd in land area, , and 45th in total area. Its population according to the 2010 census, 630,337, is the second smallest in the country, larger only than Wyoming. It is the only New England...
, New Hampshire
New Hampshire
New Hampshire is a state in the New England region of the northeastern United States of America. The state was named after the southern English county of Hampshire. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Atlantic Ocean to the east, and the Canadian...
and Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
, and in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
in in provinces of New Brunswick
New Brunswick
New Brunswick is one of Canada's three Maritime provinces and is the only province in the federation that is constitutionally bilingual . The provincial capital is Fredericton and Saint John is the most populous city. Greater Moncton is the largest Census Metropolitan Area...
and Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
.
The lake quillwort has many long, narrow leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
from 8–20 cm long and 0.5–2 mm broad, widening to 5 mm broad at the base. There is a sac that produces the spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
s at the bottom of each leaf base. The plant has a very short stem, called a corm
Corm
A corm is a short, vertical, swollen underground plant stem that serves as a storage organ used by some plants to survive winter or other adverse conditions such as summer drought and heat ....
, where all the leaves and roots are attached close together. It does not have traditional roots, but instead some of its leaves are modified to act like roots. These pseudo-roots are called rhizomorphs, and are attached to the bottom end of corm. The upper leaves are green and found sprouting in a clump.
It is found on the stony or sandy bottoms of clear, usually slightly acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
ic ponds, typically in mountain
Mountain
Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...
tarn
Tarn (lake)
A tarn is a mountain lake or pool, formed in a cirque excavated by a glacier. A moraine may form a natural dam below a tarn. A corrie may be called a cirque.The word is derived from the Old Norse word tjörn meaning pond...
s, growing at 5–460 cm depth of water. They are perennial, with typically two flushes of new leaves each year, in spring and autumn.
Reproduction usually takes place during the late summer or early fall. The sacs at the bottom of leaves create two types of spores, female (megaspores, about 0.5 mm diameter) and male (microspores, a few micrometres in diameter). These spores represent the gametophyte phase of the life cycle.
This species is one of a few cultivated species of quillworts, either as an aquarium plant or as an educational resource.