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Aquatic and Wetland Vascular Plants of the Northern Great Plains

Callitriche L. -- Water Starwort


Rather small and delicate, perennial aquatics with weak, filiform, leafy stems and fibrous roots, seldom growing on mud. Leaves small, all submersed or the upper ones floating, simple, opposite; submersed leaves sessile, clasping or connate by a narrow ridge or wing, linear, 1-nerved, entire except for the shallowly bidentate apex; floating leaves, when present, clustered in terminal rosettes or partly in separate pairs, obovate to oblanceolate or spatulate, 3- to 5-nerved, rounded, tapered at the base to a flat petiole. Flowers minute, inconspicuous, sessile and solitary in middle and upper leaf axils, naked or subtended by a pair of hyaline bracts, usually imperfect (the plants polygamo-monoecious), each consisting of 1 stamen or 1 pistil or both; pistil 2-carpellary, styles 2, deciduous, ovary flattened, oval to orbicular, 4-celled, furrowed down the middle of each face and partitioned from each edge toward the middle, separating at maturity into 4 flattened, 1-seeded nutlets.

Reference:  

Fassett, N. C.  1951. Callitriche in the New World.  
     Rhodora 53:137-155, 161-182, 185-194, 209-222.

Lead Characteristic Go To
1 Plants with linear submersed leaves only, these clasping, not connected at their bases; flowers not subtended by a pair of hyaline bracts. C. hermaphroditica
1 Plants often with some obovate to spatulate floating leaves; submersed leaves connected at their bases by a ridge or narrow wing; flowers subtended by a pair of hyaline bracts. Lead 2
2 Fruit longer than broad, its segments narrowly wing-margined at least toward the summit, pitted in rows. C. verna
2 Fruit about as broad as long, its segments rounded on the back, not wing-margined, irregularly pitted. C. heterophylla


43. Callitrichaceae, the Water Starwort Family
1. Callitriche L. -- Water starwort
1. Callitriche hermphroditica L.
2. Callitriche heterophylla Pursh
3. Callitriche verna L.


Return to Family -- Callitrichaceae - The Water Starwort Family
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