Flora of North America species comparison

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Callitriche palustris

Callitriche hermaphroditica

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

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

and leaf scales present.

and leaf scales absent.
Leaves

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

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

bracts caducous, sometimes persistent.

bracts absent.
Pedicels

0–0.2 mm in fruit.

0 mm in fruit.
Flowers

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

styles erect or spreading;

pollen yellow.

solitary;

styles erect, later recurved;

pollen colorless.
Schizocarps

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.

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.
2n

= 20.

= 6.

Callitriche palustris

Callitriche hermaphroditica
Phenology Flowering May–Oct. Flowering Jul–Sep(–Nov).
Habitat Fast-flowing rivers and streams, backwaters, ditches, swamps, Sphagnum bogs, lakes, ponds, springs, seepages. Lakes, ponds, backwaters, ditches.
Elevation 0–3600 m. (0–11800 ft.) 0–3000 m. (0–9800 ft.)
Distribution
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]
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]
Discussion

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.)

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.)
Source FNA vol. 17, p. 53. FNA vol. 17, p. 51.
Parent taxa Plantaginaceae > Callitriche Plantaginaceae > Callitriche
Sibling taxa
C. brutia, C. fassettii, C. hermaphroditica, C. heterophylla, C. longipedunculata, C. marginata, C. pedunculosa, C. peploides, C. stagnalis, C. stenoptera, C. terrestris, C. trochlearis
C. brutia, C. fassettii, C. heterophylla, C. longipedunculata, C. marginata, C. palustris, C. pedunculosa, C. peploides, C. stagnalis, C. stenoptera, C. terrestris, C. trochlearis
Synonyms C. palustris var. stenocarpa, C. palustris var. verna, C. stenocarpa, C. verna C. bifida, C. palustris var. bifida
Name authority Linnaeus: Sp. Pl. 2: 969. (1753) Linnaeus: Cent. Pl. I, 31. (1755)
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).



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