Flower:

Separate staminate (male) and pistillate (female) flowers on the same plant (monoecious). Thousands of yellowish male flowers are in a dense spike up to 10 inches long at the tip of the stem. Below the male spike is a female spike about as long or somewhat longer, with thousands of female flowers, the spike light green at flowering time turning reddish-brown to blackish in fruit. There is usually no gap between the two spikes; occasionally there may be a small separation, typically not more than 1/3 inch (8 mm), rarely longer.

Leaves:

Leaves are basal and alternate, stiff, strap-like, flat, mostly ½ to ¾ inch (10 to 23+ mm) wide, blue-green when fresh and not much rising above the flowering spikes. The sheath has a narrow band of translucent, papery edging, and the tip of the sheath where it meets the blade is tapered to distinctly shouldered (squared), but not auricled (rounded like the top of an ear) or just barely so. Stems are single, erect, stout, light green and unbranched. Vegetative colonies are often formed from long rhizomes.

Fruit:

The male flowers wither away after pollen release and eventually drop off altogether. Pistillate spikes expand up to 1½ inches (3.6 cm) thick at maturity, each flower producing a single seed attached to a stalk with long white hairs. The spikes can burst, allowing the seed to be carried off in the wind, or persist mostly intact through winter.

When the fluff is removed what remains on the stem are the stalks of individual flowers, known as "compound pedicels", which are variable in length, comprised of a few tiers and a long bristle at the tip.

Notes:

Cattails are ubiquitous and easily recognizable by their thick, cylindrical spikes. They are commonly found in wet ditches, in the shallow waters of lake and pond edges, in marshes, wet meadows and almost anywhere else soil is saturated.

Of the 3 species in Minnesota, Typha latifolia is the only native, but telling the 3 apart is not always straight forward. Generally speaking, the native has pistillate spikes that are up to 1½ inches thick in fruit, there is usually no gap between the staminate and pistillate spikes, and widest leaves are ½ inch or more broad. T. angustifolia (Narrow-leaved Cattail) has narrower spikes about half as wide in fruit, leaves consistently less than ½ inch (12 mm) wide, and the two spikes are consistently separated by at least ½ inch, sometimes by more than 3 inches. T. x glauca (Hybrid Cattail, the cross between the two) is more difficult, as it can be intermediate between its parents or take on characteristics of either one, with broader leaves and spikes, with or without a gap between spikes.

The shape of the compound pedicels on T. latifolia reminds me of the Empire State Building, complete with the long lightning rod at the tip. By comparison, those of both T. angustifolia and T. x glauca are shorter and stubbier, more like little mountains, having only 1 to 3 tiers and without the bristle at the tip, though I believe T. x glauca may have a few bristles.

I've read that DNA testing may be the best (or only reliable) way to differentiate T. latifolia and T. x glauca, but there is one other notable distinction: T. latifolia tends to play well with its neighbors, usually forming small or loose colonies, where T. x glauca almost always forms large, dense monocultures.