Callitriche palustris
Callitriche heterophylla
callitriche des marais, spring water-starwort, vernal water-starwort
different-leaf water-starwort, diverse-leaf water-starwort, greater water-starwort, large water-starwort, prairie sandgrass, two-head water-starwort, variedleaf waterstarwort, water starwort
and leaf scales present.
and leaf scales present.
connate at base, ± linear, tapering strongly from near base or spatulate, 2.5–9 × 0.3–5 mm, 1+-veined.
connate at base, ± linear, tapering from near base or spatulate, 3.7–24.7 × 0.3–3.5 mm, 1+-veined.
bracts caducous, sometimes persistent.
bracts caducous.
0–0.2 mm in fruit.
0 mm in fruit.
usually 1 staminate and 1 pistillate in 1 axil opposed by 1 pistillate;
styles erect or spreading;
pollen yellow.
usually solitary;
styles erect or spreading;
pollen yellow.
obovoid, usually widest distal to middle, 0.8–1.4 × 0.6–1.4 mm, longer than wide, sometimes as long as wide;
mericarps black, not swollen, not winged, winged only at apex, or winged throughout but widest at apex, wings straight, 0.03–0.1 mm wide.
± round, (0.4–)0.5–0.9(–1.2) × 0.5–1(–1.2) mm, as long as wide;
mericarps black, not swollen, not winged or winged only at apex, wings straight, 0.05–0.1 mm wide.
= 20.
Callitriche palustris
Callitriche heterophylla
Callitriche palustris has been included on the Composite List of Weeds maintained by the Weed Science Society of America (http://wssa.net/wssa/weed/composite-list-of-weeds/); its inclusion seems unwarranted.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Two varieties have been recognized in Callitriche heterophylla, with var. bolanderi distinguished on the basis of its schizocarps being larger (for example, N. C. Fassett 1951b); however, the size of the schizocarps overlaps widely, and measurements of schizocarps from throughout North America show that there is no clear geographical or ecological separation between plants with smaller fruit and those with larger fruit. Therefore, there is no justification for maintaining the distinction.
Populations of small plants with linear leaves from parts of Canada and Alaska have been separated as Callitriche anceps. However, these appear to represent the lower extremes of variation in C. heterophylla, and morphological characters do not justify maintaining the distinction.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
Go Botany, 
IL Wildflowers, 
MI Flora, 
MN Wildflowers, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
- Local floras: BC, CA, OR, WA
- Local Web sites: CalFlora, CalPhotos, Flora NW, Go Botany, IL Wildflowers,
KS Wildflowers, 
LA Plants, 
MD Biodiversity, 
MO Plants, PNW Herbaria - WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
