Contains 7 accepted taxa overall.

Characteristics
Hydrocotyle L.
MARSHPENNYWORT
Classification
APIALES
Hydrocotyle
Citation
HYDROCOTYLE Linnaeus, Sp. Pl. 234. 1753.
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TYPE: Hydrocotyle vulgaris Linnaeus Lectotypified by Britton & A. Brown, Ill. Fl. N. U.S., ed. 2. 2: 648. 1913.
Distribution Map Present

This species have been reported in the counties highlighted.

Species
Scientific Name Common Name Herbarium Specimens Status Photos
Hydrocotyle bonariensis LARGELEAF MARSHPENNYWORT Native FACW (NWPL) FACW (DEP)
Hydrocotyle bowlesioides LARGELEAF MARSHPENNYWORT Not Native FAC (NWPL)
Hydrocotyle ranunculoides FLOATING MARSHPENNYWORT Native OBL (NWPL) OBL (DEP)
Hydrocotyle sibthorpioides LAWN MARSHPENNYWORT Not Native FACW (DEP)
Hydrocotyle umbellata MANYFLOWER MARSHPENNYWORT Native OBL (NWPL) OD (WAP) FACW (DEP)
Hydrocotyle verticillata var. triradiata WHORLED MARSHPENNYWORT Native OBL (NWPL) FACW (DEP)
Hydrocotyle verticillata var. verticillata WHORLED MARSHPENNYWORT Native OBL (NWPL) FACW (DEP)
Identification Key
1.  Leaf blade peltate or not, with a distinct sinus, often extending to the petiole or nearly so, most blades with at least one sinus >½ of the blade width or length
2
1.  Leaf blade peltate, nearly rotund lacking a sinus or the sinus <¼ of the blade width or length
4
2.  Leaves hairy
2.  Leaves glabrous
3
3.  Stems and petioles mostly 2-4 mm wide; leaves to 8 cm long or wide
3.  Stems and petioles 0.5-1.5 mm wide; leaves to 1.5 cm long or wide
4.  Inflorescence a simple or compound umbel
5
4.  Inflorescence a spike or raceme
6
5.  Infloresnce a compound umbel
5.  Inflorescenee a simple umbel, very rarely if ever compound
6.  Flower or fruit with a pedicel up to 10 mm long
6.  Flower or fruit sessile to subsessile, the pedicel <1 mm long
Genus Synonyms
Synonym Full Citation Basionym Type
Dominia Dominia Fedde, Repert. Spec. Nov. Regni Veg. 26: 272. 1929. TYPE: Dominia acroptera (Domin) Fedde (Maidenia acroptera Domin) Substitute name for Maidenia Domin 1922, non Rendle 1916.
Homalosciadium Homalosciadium Domin, Beih. Bot. Centralbl. 23(2): 294. 1908. TYPE: Homalosciadium verticillatum Domin (Hydrocotyle verticillata Turczinanow 1849, non Thunberg 1798)
Maidenia Maidenia Domin, Acta Bot. Bohem. 1: 41. 1922, non Rendle 1916. TYPE: Maidenia acroptera Domin = Dominia Fedde 1929.
Neosciadium Neosciadium Domin, Beih. Bot. Centralbl. 23(2): 291. 1908. TYPE: Neosciadium glochidiatum (Bentham) Domin (Hydrocotyle glochidiata Bentham)
Uldinia Uldinia J. M. Black, Trans. & Proc. Roy. Soc. South Australia 46: 568, t. 37(2). 1922. TYPE: Uldinia mercurialis J. M. Black