Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Callitriche hermaphroditica

Callitriche palustris

autumn water-starwort, autumnal water-starwort, callitriche hermaphrodiate, northern water-starwort, scarlet waterstarwort

callitriche des marais, spring water-starwort, vernal water-starwort
Stem

and leaf scales absent.

and leaf scales present.
Leaves

not connate at base, ± linear, tapering from base, (7–)7.6–11.5 × 0.9–1.4 mm, 1-veined.

connate at base, ± linear, tapering strongly from near base or spatulate, 2.5–9 × 0.3–5 mm, 1+-veined.
Inflorescences

bracts absent.

bracts caducous, sometimes persistent.
Pedicels

0 mm in fruit.

0–0.2 mm in fruit.
Flowers

solitary;

styles erect, later recurved;

pollen colorless.

usually 1 staminate and 1 pistillate in 1 axil opposed by 1 pistillate;

styles erect or spreading;

pollen yellow.
Schizocarps

1.1–1.9 × 1.2–2.4 mm, shorter than or as long as wide, sometimes longer than wide;

mericarps dark brown, not swollen, winged throughout, wings straight, 0.2–0.8 mm wide, as wide as or wider than mericarp body.

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.
2n

= 6.

= 20.

Callitriche hermaphroditica

Callitriche palustris
Phenology Flowering Jul–Sep(–Nov). Flowering May–Oct.
Habitat Lakes, ponds, backwaters, ditches. Fast-flowing rivers and streams, backwaters, ditches, swamps, Sphagnum bogs, lakes, ponds, springs, seepages.
Elevation 0–3000 m. (0–9800 ft.) 0–3600 m. (0–11800 ft.)
Distribution
from FNA
AK; CO; ID; MT; NE; NJ; NY; OR; UT; VT; WI; WY; AB; BC; NF; NT; ON; QC; SK; Greenland; Eurasia
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AZ; CA; CO; CT; DE; IA; ID; IL; MA; ME; MI; MN; MT; ND; NE; NH; NJ; NM; NV; NY; OR; PA; RI; SD; TX; UT; VT; WA; WI; WY; AB; BC; MB; NB; NF; NT; NU; ON; PE; QC; SK; YT; SPM; Greenland; Mexico (Chihuahua, San Luis Potosí); Eurasia [Introduced in Australia]
[WildflowerSearch map]
[BONAP county map]
Discussion

Infraspecific divisions have been based on the size of fruit (for example, R. V. Lansdown 2006); assignment of North American populations to these taxa would be premature.

Callitriche autumnalis Linnaeus is a superfluous renaming of C. hermaphroditica, with which it is homotypic (R. V. Lansdown and C. E. Jarvis 2004).

Callitriche fassettii, C. hermaphroditica, and C. stenoptera are morphologically very close; however, C. hermaphroditica always has sessile fruit, whereas the fruit of both the other species may be pedicellate. The mericarp wing of C. stenoptera is consistently very narrow and that of C. fassettii is slightly wider than that of C. hermaphroditica, which is generally wide, particularly at the apex.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

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.)
Source FNA vol. 17, p. 51. FNA vol. 17, p. 53.
Parent taxa Plantaginaceae > Callitriche Plantaginaceae > Callitriche
Sibling taxa
C. brutia, C. fassettii, C. heterophylla, C. longipedunculata, C. marginata, C. palustris, C. pedunculosa, C. peploides, C. stagnalis, C. stenoptera, C. terrestris, C. trochlearis
C. brutia, C. fassettii, C. hermaphroditica, C. heterophylla, C. longipedunculata, C. marginata, C. pedunculosa, C. peploides, C. stagnalis, C. stenoptera, C. terrestris, C. trochlearis
Synonyms C. bifida, C. palustris var. bifida C. palustris var. stenocarpa, C. palustris var. verna, C. stenocarpa, C. verna
Name authority Linnaeus: Cent. Pl. I, 31. (1755) Linnaeus: Sp. Pl. 2: 969. (1753)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America, OregonFlora, UW Burke Herbarium

The species comparison tool is brought to you by:
Northwest Wildflowers