''Isoetes lacustris'', the lake quillwort or Merlin's grass, is a boreal
quillwort native on both sides of the northern
Atlantic Ocean.
Synonyms
A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...
include ''Isoetes hieroglyphica''.
Description
The lake quillwort has many long, narrow
leaves
A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
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
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...
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.
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.
Taxonomy
''Isoetes lacustris'' was discovered by
Johannes Reinke, and first described by
Carl Linnaeus. ''Isoetes hieroglyphica'' was considered to be a separate species,
but is now considered to be a synonym of ''I. lacustris''.
Distribution and habitat
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. Further south, isolated populations occur in the glacial lakes of the
Pirin mountain range in
Bulgaria.
In the
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
, it occurs in the
New England states of
Maine,
Vermont,
New Hampshire Rhode Island and
Massachusetts, and in
Canada in provinces of
New Brunswick and
Nova Scotia.
It is found on the stony or sandy bottoms of clear, usually slightly
acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...
ic ponds, typically in
mountain tarns, growing at 5–460 cm depth of water. They are perennial, with typically two flushes of new leaves each year, in spring and autumn.
Uses
This species is one of a few cultivated species of quillworts, either as an aquarium plant or as an educational resource.
References
External links
Flora Europaea: ''Isoetes lacustris''NCRS: USDA Plants Profile and map: ''Isoetes lacustris''
{{Taxonbar, from=Q1192790
lacustris
Flora of the Northeastern United States
Flora of Tennessee
Flora of Virginia
Flora of Saint Pierre and Miquelon
Flora of the Great Lakes region (North America)
Flora of Greenland
Flora of Eastern Canada
Flora of the Northwest Territories
Flora of Manitoba
Flora of Saskatchewan