Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Ceratophyllum muricatum Cham. subsp. australe (Griseb.) Les

Common name(s): [more details]

English: prickly hornwort

Habit:  aquatic herb

Description: 

"Ceratophyllum demersum L.:  "Submerged herb, richly branched, to 2 m long or sometimes longer; main stems terete, 1-3 mm diameter, smooth.  Leaves dark to bright green, rather coarse, 3-12 per node, 8-15 (-20) mm long, each leaf mostly divided twice forming four ± linear leaflets, these 4-12 (-15) mm long, serrulate, apically and dorsally provided with solitary, minute hairs.  Staminate and pistillate flowers mixed in the axils of each leaf whorl; staminate flowers with 6-12 pale green tepals and 10-12 stamens.  Fruits fleshy, brownish or dark green, the body smooth or somewhat tuberculate, broadly ellipsoid, 3.5-6 x 2-4 mm, with one apical (persistent style) and two basal spines 0.1-14 mm long."

"Ceratophyllum muricatum Cham. subsp. australe (Griseb.) Les (=Ceratophyllum llerenae Fassett): Similar to C. demersum but leaves yellowish green, dichotomously divided two to four times, segments usually inflated at base, fruits with surfaces tuberculate or papillate, and fruit margins sometimes winged and spinulose"  (Ståhl, 2003; pp. 27-28).

Habitat/ecology:  Submerged aquatic (Ståhl, 2003; pp. 27-28).

Propagation:  Seed?

Native range:  Southeastern US to South America (Ståhl, 2003; pp. 27-28). Naturalized elsewhere (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	possibly introduced invasive	Charles Darwin Foundation (2008)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Central America Central America (Pacific rim)	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	El Salvador (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Colombia	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Ecuador (Republic of) (continental)	native	Ståhl, Bertil (2003) (p. 28)
South America (Pacific rim) South America (Pacific rim)	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Comments:  Probably not native to the Galápagos Islands, probably introduced per Charles Darwin Research Institute.

Control:  If you know of control methods for Ceratophyllum llerenae, please let us know.