Sparganium (bur-reed)

AE leaves

..... lvs strongly triangular sl triangular or rounded on the back flat
1)stigmas & locules 2; fr broadly obpyramidal great bur-reed (1.eurycarpum) freq over 3' high; nutlets broad & flat on top; in mud or shallow water; QE & NS to VA ..... .....
1)stigma 1; fr fusiform or ellipsoid

2)achene with beak 0-1.5mm and stalk 0-1mm; staminate head solitary

 ..... ..... (9.minimum) in shallow water; s to NJ, PA
2)achene with beak 1-5.6mm & stalk 1-5mm; most spp. w/ 2 or more male heads

4) anthers & stigma oblong or ovate, 0.4-0.8mm; tep inserted from base to middle of the stipe; lvs scarcely or not at all keeled

 ..... ..... (7.fluctuans) staminate heads several, separated from the pistillate; achene dull; in quiet water; NF & QE to CN, PA
5) anthers & stigma linear, 0.8-4mm; tep inserted chiefly above the middle of the stipe, the 3 inner ones at its very summit; lvs often keeled (longitudinal ridge) ..... ..... .....
6)pistillate heads all axillary & subtended by bracts ..... ..... .....
achene lustrous, pale brown, its body 5.5-7mm; stigma 1.5-3mm branching bur-reed (2.androcladum) nutlets taper on top ..... .....
achene dull, sordid brown, its body 3-5mm; stigma 1-1.5mm ..... lesser bur-reed (3.americanum) us. under 3' high; nutlets tapering at both ends .....
6) pistillate heads partly supra-axillary ..... ..... .....
8)achene-beak about as long as the body; plants normally erect ..... (4.chlorocarpum) mud or shallow water; NF & QE to WV (4.chlorocarpum) mud or shallow water; NF & QE to WV
8) achene beak evidently shorter than the body; plants ordinarily with floating leaves

 

 ..... (5.angustifolium) lvs rounded on the back, 2-6mm wide, the upper dilated at base; in deep or shallow water, occ on mud; NF to NJ, PA (6.emersum) lvs flat (or keeled toward the base), 6-12mm wide, not dilated at base; in quiet water; s to N Eng, NY