420204 Cerastium arvense L.
- L., Sp. Pl.: 438 (1753). Lectotype (LINN): Sweden: Skåne. Herb. Linn. 603.9 (Ugborogho 1977: 177).
(1) 36 (2x). - Europe. - Jalas (1993, secondary report for subsp. suffruticosum).
(2) ca. 64. - Europe (C). - Dobes and Hahn (1997).
(3) 72 (4x). - Europe, Canada. - Numerous reports for subsp. arvense and subsp. molle.
(4) 90 (5x). - North America. - Ugborogho (1973).
(5) 108 (6x). - Europe. - Jalas (1993, secondary report for subsp. suffruticosum).
Geography: Circumboreal & South American.
Notes: Cerastium arvense is distributed throughout temperate, alpine, and southern arctic regions in the northern hemisphere and south to southernmost South America. Two main ploidy levels are known: diploid and tetraploid. Jalas (1993) divided the polymorphic European material on six subspecies, among them the diploid subsp. strictum Gaudin in the central and southern European mountains and the tetraploid subsp. arvense throughout Europe. However, the northeastern European Russian plants are counted as diploids as are the other arctic and northern plants. Löve and Löve (1975a) treated the two ploidy levels as species: the diploids as C. strictum Haenke (described from the central European mountains) and the tetraploids as C. arvense L. Morton (2005a) accepted two races for North America: an adventive subsp. arvense (tetraploid) and a native subsp. strictum (diploid). Morphological criteria for separation of the subspecies are given by Jalas and Morton. We accept the native northern diploids under the name subsp. strictum. However, we do not know whether the widespread North American (and Russian-Siberian) plant is the same as the European mountain plant which Jalas (and originally Gaudin) considered under the name subsp. strictum.