Coleanthus

Coleanthus
Coleanthus subtilis[1]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Monocots
Clade:	Commelinids
Order:	Poales
Family:	Poaceae
Subfamily:	Pooideae
Supertribe:	Poodae
Tribe:	Poeae
Subtribe:	Coleanthinae
Genus:	Coleanthus Seidl[2][3]
Species:	C. subtilis
Binomial name
Coleanthus subtilis ( Schult.
Synonyms[4]
Schmidtia Tratt. 1816, rejected homonym not Moench 1802 (Asteraceae) nor Steud. ex J.A. Schmidt 1852 (Poaceae) Wilibalda Sternb. ex Roth Schmidtia subtilis Tratt. Zizania subtilis (Tratt.) Raspail Wilibalda subtilis (Tratt.) Roth Schmidtia utriculata J.Presl & C.Presl Schmidtia utriculosa Sternb.

Coleanthus is a

A

Coleanthus subtilis typically blossoms from June through September, with very few occurrences in early May or late November. It is diploid, with a chromosome number of 2n = 14.^[13]

Distribution

The distribution area of Coleanthus subtilis extends over several small, highly disjunct sub-areas:

• Northwest France (Brittany)
• Central Europe: the species is primarily found in the Czech Republic, with formerly about 140 localities, and extend to Austria^[14] (only at some ponds in the Waldviertel, threatened with extinction), Slovakia,^[13] and Poland (near Wroclaw).^[15] In Germany, it is extinct in the Westerwald (Rhineland-Palatinate) and near Mannheim (Baden-Wüttemberg),^[16] but it has lately been found in Saxony in Freiberg, Upper Lusatia, and Saxony-Anhalt near Wittenberg.^[17]
• South Tyrol, extinct^[14] (at two lakes near Bolzano and at Lake Dobbiaco)
• Norway, last in1842: near Oslo^[17]
• The area south of Lake Ladoga near Saint Petersburg^[17]
• West- Siberia
• on the middle and lower Amur (China)
• in North America, Coleanthus subtilis has been found in six areas in southern British Columbia (Canada) and on the Columbia River in Washington and Oregon (USA). It was discovered in 2007 in Canada's Northwest Territories, about 1700 km from the closest site. Due to its late American discovery (1880), it was considered that it had been brought over from Europe. However, several factors suggest that the species is also native to North America, including its very specialized habitat requirements, and rarity, which may have led to the late discovery of the species in America, and the absence of circumstantial evidence that it was actually introduced from Europe.^[18][19]

Coleanthus subtilis is listed in Annex II and IV of the Habitats Directive and is thus classified as a priority species. Due to its endangered status, it is given particular protection in Germany under the Federal Species Protection Ordinance.^[20]

Ecology and sociology

Coleanthus subtilis is a therophyte with a six to seven-week life cycle.^[21] Generally, it grows in short-lived, patchy dwarf rush colonies that occupy 60–80% of the available space.^[22] It occurs in widely scattered locations, often in the mud of drained ponds, stream and river banks, and old-water margins. The plant is extremely rare and unstable. It vanishes as soon as the ground floods again. Under ideal conditions, it possesses a lifespan of two to four years.^[12] According to earlier research, the seeds can survive in flooded soil for up to 20 years without losing their ability to germinate.^[13]

It is spread by rivers at relatively short distances (

In the Cypero-Limoselletum from the Nanocyperion association, Coleanthus subtilis is the most prevalent.[24]

Systematics, name, and botanical history

Coleanthus subtilis was discovered in 1811 by brothers Jan Svatopluk and Karl Bořiwog Presl near Osek in the Pilsen district and it was first named in 1816 by Leopold Trattinnick under the name (basionym) Schmidtia subtilis.^[25] The plant was classified to the genus Coleanthus by Wenzel Benno Seidl in 1817 (in Roemer & Schultes: Systema vegetabilium).^[26][20]

The Greek words koleós, which means sword sheath, and ánthos, which means flower or blossom, are combined to form the name Coleanthus.^[27] The species epithet subtilis (Latin for fine, thin, delicate) refers to the thread-thin stems. The genus name translates directly to the German name Scheidenblütgras. The less precise translation of the species name, "sheath grass," emphasizes one of its most distinctive characteristics: expanded leaf sheaths.^[28]

In the