Scientific name: Sparganium emersum Rehmann
Common name: Unbranched Bur-reed
Description
Habit: Glabrous, aquatic or semi-aquatic, rhizomatous, herbaceous perennials rooted in mud; stems erect, up to 35-75cm.
Leaves: Alternate, simple, entire, sessile, linear, without stipules, erect, floating, 8-10mm wide; the lowest keeled at base; aerial leaves strongly keeled at least in lower part, not inflated at base.
Flowers: Monoecious, actinomorphic; in a terminal spike, raceme or panicle of globose unisexual heads, the upper 3-7 contiguous heads exclusively male, the lower, larger 3-4 stalked heads exclusively female; perianth represented by 3-6 scales; male flowers with 3-8 stamens; female flowers with 1-2(-3) fused carpels with as many cells, ovules, stigmas and styles, stigmas linear to subcapitate.
Fruits: Fruit a drupe, small, dry, spongy, ellipsoid, tapered to beak, often pedicellate, style straight, fruiting heads 18-20mm across.
Habitat: Ditches, slow streams and lake-margins.
Distribution: Occasional.
Native status: Native
Of conservation interest: No