Callitriche heterophylla
Callitriche peploides
different-leaf water-starwort, diverse-leaf water-starwort, greater water-starwort, large water-starwort, prairie sandgrass, two-head water-starwort, variedleaf waterstarwort, water starwort
Matted water-starwort
and leaf scales present.
and leaf scales present.
connate at base, ± linear, tapering from near base or spatulate, 3.7–24.7 × 0.3–3.5 mm, 1+-veined.
connate at base, spatulate-obovate, 1.4–2.3 × 0.4–1.5 mm, 2+-veined.
bracts caducous.
bracts absent.
0 mm in fruit.
0 mm in fruit.
usually solitary;
styles erect or spreading;
pollen yellow.
not solitary, usually 1 staminate and 1 pistillate in 1 axil opposed by 1 pistillate;
styles erect to reflexed;
pollen yellow.
± 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.
0.4–0.7 × 0.7–0.9 mm, shorter than wide;
mericarps black, swollen at base, not winged or winged only at apex, wings straight, 0–0.03 mm wide.
= 10.
Callitriche heterophylla
Callitriche peploides
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.)
Three varieties of Callitriche peploides have been recognized (N. C. Fassett 1951b). A collection reported as a weed of a container in a nursery in San Bernardino County, California (T. C. Fuller 1967) is referable to var. semialata. The characters used to distinguish these varieties do not appear reliable, and it seems best to disregard them (R. V. Lansdown and M. J. M. Christenhusz 2011).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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