Flowers:

Separate staminate (male) and pistillate (female) flowers on the same plant (monoecious), in a single branching cluster 9 to 24 inches long at the tip of the stem. Staminate flowers are on the lower branches, the branches ascending to spreading and the spikelets (flower clusters) loosely arranged, with 5 to 50 spikelets on the lower branches. The upper branches are all pistillate, the branches somewhat ascending or erect and appressed to the stem at flowering time; spikelets are appressed to the branch with 2 to 30 spikelets on the lower pistillate branches. All spikelets have a single floret.

A pair of bracts (glumes) at the base of a staminate spikelet is missing. Surrounding a staminate floret is pair of bracts (lemma and palea), both thin, hairless, straw-colored to purple, similar in size and shape, 6 to 16 mm (¼ to ~2/3 inch) long, lance-oblong, pointed at the tip or the lemma sometimes short-awned. The lemma and palea are spreading, revealing 6 bright yellow stamens. Staminate flowers drop off after releasing their pollen leaving naked stalks behind on the branches.

A pair of bracts (glumes) at the base of a pistillate spikelet is also missing. Surrounding a pistillate floret is pair of bracts (lemma and palea), both firm, lance-oblong, 6 to 30 mm (to ~1 inch) long, 3-veined. The lemma is shiny, hairy along the veins at the tip end with a few hairs also at the base end, mostly hairless between the veins, and the tip extending to a straight, hairy awn up to 4 inches long. The palea is awnless and hairless with the edges of the lemma wrapping around the palea edges. A feathery style pokes out near the base of the spikelet.

Leaves and stems:

Early season leaves are typically floating on the water's surface but are later emersed and more firm but still soft. Leaves are basal and alternate, 8 to 24 inches long, 3 to 40 mm (to 1½ inches) wide, ascending to spreading, flat, hairless, rough-textured along the edges. Sheaths are hairless. The ligule (membrane where the leaf joins the sheath) is 4 to 10+ mm long and lacks a fringe of hairs. Nodes are smooth. Stems are smooth, unbranched, and may form large, dense stands.

Fruit:

Pistillate spikelets turn tan at maturity, dropping off individually leaving the naked stalks on the branches. Branches may remain appressed as spikelets mature but often become more spreading when fruit is ready to drop. Not all florets mature; aborted fruits are common, the aborted spikelets .9 to 1.8 mm wide.

Grains (seeds) are narrowly oblong-elliptic, dark brown at maturity, to 30 mm long and 2 mm wide.

Notes:

Wild Rice has special significance as a culturally and economically important plant to Native Americans, but also as a valued food source and nesting habitat for water fowl. Minnesota has more acreage of natural Wild Rice than any other state in the country, present in more than half our counties, but it's most abundant in the north-central part of the state. It is a large but fragile species, susceptible to a host of environmental conditions, in particular fluctuating water levels—the wrong water level at the wrong stage of development can destroy a year's crop. Seeds can remain viable for 5 years so one bad year may not permanently harm a population, but they must stay moist—they will not germinate if they dry out. Wild Rice is also a source of much contention to developers who would (potentially) degrade water quality. Recent efforts to ease our strict pollution standards in Wild Rice waters have so far failed, and we hope that continues to hold.

Wild Rice can be harvested by permit and those fees help fund management efforts to maintain healthy populations. Harvesting must be done in a canoe or other non-motorized boat, propelled only by a push pole, and the mature grains collected in the boat by knocking them off the stem with special wooden sticks known as flails. The penalty for violating the harvesting laws or rules is a $1000 fine and/or 90 days in jail. You can learn more about Minnesota's Wild Rice at the DNR website.

There are two varieties of Zizania palustris, both of which are in Minnesota: var. palustris has widest leaves seldom more than 1 cm (3/8 inch) wide, ligules seldom more than 5 mm long, lower staminate branches with up to 15 spikelets, lower pistillate branches with up to 8 spikelets, pistillate branches mostly appressed, and pistillate awns up to 4 cm (~1½ inches) long; var. interior is the more robust of the two with widest leaves usually more than 1 cm wide, ligules to 10+ mm long, lower staminate branches with usually more than 25 spikelets, lower pistillate branches usually with 9 to 30 spikelets, pistillate branches more ascending than erect, and pistillate awns up to 10 cm (4 inches) long.

Z. palustris was once considered a variety of Zizania aquatica (Southern Wild Rice) and is lumped with it in some references, but the latter is distinguished by its more robust form, growing to heights of as much as 14 feet, leaves to 5.5 cm wide, ligules to 28 mm long, somewhat smaller spikelets (both staminate and pistillate), with pistillate lemmas at least sparsely hairy between the veins all across the surface, and aborted spikelets less than 1 mm wide. Z. aquatica has been recorded only once in Minnesota, in Houston County in 1899, but is fairly common in Wisconsin.