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Aquatic and Wetland Vascular Plants of the Northern Great Plains

64. Sparganiaceae, the Burreed Family

1. Sparganium L. -- Burreed

2. Sparganium emersum Rehm.


Quite similar to the preceding, differing chiefly as follows: Leaves averaging broader, mostly (5)6-12 mm wide, these and the bracts usually strongly dilated at the base with broad scarious margins. Achenes smaller, the body 2-3.5 mm long at maturity, the beak (including the stigma) 2-3 mm long. Jul--Sep. Usually in shallow water of streams and ponds; occasional in the Black Hills and reputedly e MT; (Labr. to AK, s to PA, Ont., Man., SD, NM, AZ and CA). S. multipedunculatum (Morong) Rydb., S. simplex Huds.

Our representatives are assigned to var. multipedunculatum (Morong) Rydb.

The distinctions between this entity, S. chlorocarpum and S. angustifolium Michx. are far from clear. The latter is generally separated from the other two by its floating-leaved habit, smaller pistillate heads 1-2 cm in diameter and shorter fruit beaks 0.5-2 mm long. S. emersum in many respects seems to represent an intermediate between S. angustifolium and S. chlorocarpum, yet the latter two appear quite distinct where they are sympatric in eastern North America and where S. emersum is supposedly absent. Until this complex is studied in greater detail, we have the unsatisfactory situation of relying too heavily on geographical criteria for separating S. chlorocarpum and S. emersum with the latter being the western North American counterpart of the former.

GIF- Distribution Map

Map key


Previous Section -- Sparganium chlorocarpum Rydb. -- Greenfruit burreed
Return to Family -- Sparganiaceae - The Burreed Family
Next Section -- Sparganium eurycarpum Engelm. -- Giant burreed

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