Three kinds of pads

I used to think all the plants with pads that grew on the water were one and the same species. There were those with big, tough pads, some with yellow blossoms, some with white. Then there were smaller pads, surely just the new and growing stage of the same plant. I thought this way until I attended an aquatic plant seminar at my first Wisconsin Lakes convention three Aprils ago. Then the scales (pads?) fell from my eyes.

It turns out three varieties of water plants with floating pads inhabit Wisconsin waters. The ones with the pure white blooms are water lilies, specifically American white water lilies. They grow long stems that shoot up from this root structures (rhizomes) buried in the bottom. The round leaves (pads) are up to 10 inches in diameter, with a slit that reaches almost all the way to the central stem. The blossoms open early in the morning and close up at about noon.

Unlike most land plants, water lily leaves have their stomata (pores where carbon dioxide enters the plant) on their glossy upper sides. The spongy leaf stalks have four air channels that carry oxygen to the rhizomes (which, by the way, muskrats love eating).

Spatterdock (also called cow lily) has pads similar in size to those of water lilies, and also with a slit, but they are heart-shaped, have wavy (rather than smooth) margins, and tend to be bigger. The stems and leaves grow from buried rhizomes. The real identifier of spatterdock, versus water lily, is the bright-yellow flowers, which when closed up on the ends of their stalks remind me of lollipops on sticks. The flowers aren’t as showy as the lilies – they don’t open up wide the way the white blooms do.  

Watershield (also known as dollar pad or water target) is a much more delicate plant. The pads grow no bigger than about six inches long by three wide. Perhaps most interesting, the stems are a little bit stretchy, so in rough water can bob up and down without breaking off. When the plants are young, the stems and pad undersides are coated with a gelatin-like substance that makes them quite slippery.

How does this plant get is name? Because the pads attach to the stem right  in the middle, giving them a shield-like look. The plants sprout little dark-purple flowers in summer that stand just above the water’s surface. Any fisherman will tell you watershield isn’t as tough as water lily or spatterdock; if a lure gets stuck in watershield, you can usually pull it free before your line snaps. How do I know this? Because fish love to hang out in watershield, and I cast into it if I find it.

So now you know one pad from another. And maybe, unlike me, you’ve known for a long time.