Dig deeper at SERNEC, a consortium of southeastern herbaria.

This is a tiny floating plant with flattened stems (fronds), which are fairly thick and purplish below. Note that the former S. oligorrhiza, now named Landoltia punctata, is an exotic species. Its fronds have 2-7 roots and each is elliptical (1.5-3x long as wide), whereas S. polyrrhiza has 7-21 roots per frond and has a rounded frond less than 1.5x long as wide. Learn more at Vascular Plants of North Carolina.

The largest of the "duckweeds" (Landoltia, Lemna, Spirodela, Wolffia, Wolffiella). Read more in Weakley's Flora.

SYNONYMOUS WITH (ORTHOGRAPHIC VARIANT) PLANTS NATIONAL DATABASE:
Spirodela polyrrhiza   FAMILY Lemnaceae

SYNONYMOUS WITH Floristic Synthesis of North America. BONAP (Kartesz, 2021)

Spirodela polyrhiza

SYNONYMOUS WITH (ORTHOGRAPHIC VARIANT) Flora of North America north of Mexico, vol. 22 (2000)

Spirodela polyrrhiza

SYNONYMOUS WITH (ORTHOGRAPHIC VARIANT) Floristic Synthesis of North America (Kartesz, 1999)

Spirodela polyrrhiza

SYNONYMOUS WITH (ORTHOGRAPHIC VARIANT) VASCULAR FLORA OF THE CAROLINAS (Radford, Ahles, & Bell, 1968) 033-01-002:

Spirodela polyrrhiza   FAMILY Lemnaceae

SYNONYMOUS WITH Manual of the Southeastern Flora (Small, 1933, 1938)

Spirodela polyrhiza

COMMON NAME:
Greater Duckweed, Duckmeat, Minnow-fole, Giant Duckweed

         To see larger pictures, click or hover over the thumbnails.

Terry Holdsclaw    tdh_s_polyrrhiza_1

June    Catawba County    NC

Upper surface of fronds sometimes with red spot in center, 7-16(21) veins, per Flora of North America.

Terry Holdsclaw    tdh_s_polyrrhiza_2b

June    Catawba County    NC

Fronds obovate to circular, flat or rarely gibbous, 1-1.5x as long as wide, per Flora of North America.

 COMPARE aquatic plants

Terry Holdsclaw    tdh_s_polyrrhiza_8294

July    Catawba County    NC

Fronds 2-10mm, per Flora of North America.

WEAKLEY'S FLORA OF THE SOUTHEASTERN US (4/14/23):
Spirodela polyrhiza   FAMILY Araceae

SYNONYMOUS WITH (ORTHOGRAPHIC VARIANT) PLANTS NATIONAL DATABASE:
Spirodela polyrrhiza   FAMILY Lemnaceae

SYNONYMOUS WITH Floristic Synthesis of North America. BONAP (Kartesz, 2021)
Spirodela polyrhiza

SYNONYMOUS WITH (ORTHOGRAPHIC VARIANT) Flora of North America north of Mexico, vol. 22
Spirodela polyrrhiza

SYNONYMOUS WITH (ORTHOGRAPHIC VARIANT) Floristic Synthesis of North America (Kartesz, 1999)
Spirodela polyrrhiza

SYNONYMOUS WITH (ORTHOGRAPHIC VARIANT) VASCULAR FLORA OF THE CAROLINAS (Radford, Ahles, & Bell, 1968) 033-01-002:
Spirodela polyrrhiza   FAMILY Lemnaceae

SYNONYMOUS WITH Manual of the Southeastern Flora (Small, 1933, 1938)
Spirodela polyrhiza