The Flickr Prairieplants Image Generatr

Photo by Rachel Morris

Photo by Rachel Morris

Bumble bee queen, possibly "Bombus borealis" or "Bombus nevadensis", enjoying some nectar from wax-leaf beardtongue. Photo by Rachel Morris

Photo by Rachel Morris

Alternate ID suggested on iNaturalist as carrotleaf desert-parsely.

Photo by Rachel Morris

Photo by Rachel Morris

Stiff goldenrod and stiff-leaved goldenrod and little bluestem or beard grass

Facing eastward. A contextual or habitat shot taken near the park's northern boundary, west of a marsh and in an open spot of an Black Oak savanna.

The plant of special interest featured in this photo is the tall-growing one at frame center, with a fully developed inflorescence leaning over toward the right. It is one of the leading cast members of the great American prairie, Switch Grass (Panicum virgatum). It's native to much of this continent.

I've always found the inflorescence architecture of the big genus Panicum particularly interesting, even though keying out some of its species can be a chore.

Fortunately, though, P. virgatum is easily identifiable, especially when you're wending your way through a Midwestern grassland of the wetter variety in late summer.

As is evident here, the inflorescence is a panicle that has an open, airy, and pyramidal aspect. Each of its spreading branches bears a few spikelets. These structures contain the florets—miniature flowers of a particularly minimalist design—and later the tiny fruits known as caryopses. Each caryopsis consists of a single seed sheathed in a hard, protective coat.

We'll get a closer look at the panicle shown here in this set's next photo.

You'll find the other photos and descriptions of this series in my Botany of Illinois Beach State Park album.