Photo of the Week – March 31, 2017

Prairie clover is a term that gets used pretty broadly among the public.  Ok, not necessarily the among the GENERAL public, but among people who have at least some idea what grasslands look like.  I’ve heard the term prairie clover applied to a number of different legume species, including sweet clover.  Botanically, prairie clover – as far as I know – refers only to plants in the genus Dalea, and including familiar species like purple prairie clover (Dalea purpurea) and white prairie clover (Dalea candida).

In Nebraska, we have eight species of prairie clover.  I finally saw large-spike prairie clover this past summer (though not in bloom), which means I’ve now seen all of them.  I’m still waiting for my certificate to arrive in the mail.  I’ve only been able to photograph five of the eight, but I’ll try to do better in the future.  Maybe I can earn the prairie clover photography patch someday.  (I’m just assuming that patch exists.  If it doesn’t, someone needs to answer for that.)

Purple prairie clover is well-known and well-distributed across Nebraska. It is a big favorite among bees, and while cattle will often eat it – especially under relatively high stocking rates – it survives periodic grazing very well in our prairies.

White prairie clover is also widespread across Nebraska and popular among pollinators. This one is hosting both a long-horned beetle and weevil.

While purple and white prairie clover are the best known of this group of wildflowers, the lesser known and more specialized prairie clovers are also worth seeing and learning about.  Golden dalea (Dalea aurea) has gorgeous yellow flowers, but you’re not likely to run across it unless you go searching for it in one of the scattered locations it occurs.  Hare’s foot dalea (Dalea leporina) is an annual prairie clover that is a real enigma to me, and I’ve only seen it in our restored prairies.  Silky prairie clover (Dalea villosa) might be my favorite of all.  It has beautiful long pale pink-lavender flowers and fuzzy sea-green leaves and is common throughout much of the Nebraska Sandhills, as well as other sandy places.

Golden dalea is a beautiful prairie clover found on prairie hillsides here and there around the state.

Hare’s-foot dalea, aka annual dalea, is not a showy prairie clover, but is still pretty. It comes and goes in our restored prairies, often responding positively during the recovery periods following bouts of fire and grazing.

Silky prairie clover has a subtle beauty that fits well in the sandy prairies it inhabits.

The remaining three species in Nebraska are large-spike prairie clover (Dalea cylindriceps), round-head prairie clover (Dalea multiflora), and nine-anther dalea (Dalea enneandra).  Round-head prairie clover just barely comes into the southern tier of Nebraska counties.  The other two are found in scattered locations around the state.

It would be hard to think of a group of wildflowers that contributes more to prairie communities than prairie clovers.  At least purple and white prairie clover provide very high quality forage for herbivores, including livestock.  Bees and other pollinators focus heavily on prairie clovers, and the pollen and nectar are abundant and easily accessible.  The seeds are big and nutritious, and eaten by birds, small mammals, and insects.  During drought years, purple and white prairie clover are among the wildflowers that are mostly still green and blooming, even when surrounded by brown crispy plants, so they keep contributing even in difficult times.  Oh, and of course, as legumes, prairie clovers are nitrogen fixers.  From a land manager’s standpoint, prairie clover is easy to harvest seed from, germinates easily in restored prairies, and survives well under our fire and grazing management here on the Platte River.

If you haven’t seen all the different prairie clovers in your area, I hope you get a chance to remedy that soon.  Personally, I can’t wait until summer wildflower season arrives so I can keep working toward earning that prairie clover photography patch.  Maybe I can talk my wife into knitting me a prairie clover-themed stocking cap to sew the patch onto!

(For you young people out there, a patch is a kind of decorative embroidered thingie folks used to sew onto their clothing to recognize an award or achievement, or to signify membership in a particular club or group.  Trust me, it was super cool.  Your friends would be impressed if you showed up to a party wearing one.)

Photo of the Week – February 9, 2017

Snow-on-the-mountain (Euphorbia marginata) is a showy plant, but not because of its flowers.  In fact, the flowers are tiny and very simple.  It’s the leaves (and some bracts beneath the flowers) that make the plant outstanding in its field.

Sno-

Snow-on-the-mountain (Euphorbia marginata)

Like other relatives in the spurge family, snow-on-the-mountain’s flowers have no petals or sepals.  The small round white things that look like petals beneath the anthers are actually bracts, and all the other white parts are leaves.  Most of the leaves of snow-on-the-mountain are green, but they become variegated toward the top of the plant.  The leaves closest to the flowers are often nearly or completely white.

More snow-on-the-mountain.

More snow-on-the-mountain, showing the rounded white bracts beneath the flowers, and the variegated green and white leaves below those.

The weird flower structures and variegated leaves are not the only unique features of snow-on-the-mountain.  Some of you with biology backgrounds know that plants are often divided by their photosynthesis strategy.  There are C4 plants (often casually referred to as “warm-season” plants) which are most efficient at photosynthesis during hot temperatures and drought conditions, and there are C3 plants (“cool-season” plants) which are more efficient during other kinds of conditions.  A few of you might even know that there is a third photosynthetic pathway called CAM, which is particularly effective in very arid conditions.  As it happens, snow-on-the-mountain and other Euphorbs actually use all three photosynthetic pathways – the only genus of plants for which that is true (as far as I know).  There, now you all have something to talk about at your next family gathering.

Snow-on-the-mountain is often maligned as a weed that needs to be controlled via herbicide or mowing.  In truth, while it is closely related to leafy spurge (Euphorbia esula), snow-on-the-mountain is an annual plant that is opportunistic but not invasive.  Cattle don’t like the taste of it, so it is often left ungrazed when everything else around it is nipped off near the ground.  Snow-on-the mountain can thrive in overgrazed pastures and other places where the vigor of dominant grasses is suppressed, but it competes poorly against those grasses when they’re allowed to grow again.

I appreciate periodically seeing snow-on-the-mountain in prairies because I know that if it was able to germinate and grow, other plants (including less “weedy” perennials) probably got the same opportunity.  Except around water tanks or other places where repeated cattle impacts or other factors keep grasses suppressed, snow-on-the-mountain doesn’t hang around very long.

A small beetle feeds on pollen, seemingly unaware of the camouflaged danger lurking nearby (crab spider).

A small beetle feeds on snow-on-the-mountain pollen, seemingly unaware of the camouflaged danger lurking nearby (crab spider).

As if the weird flowers, variegated leaves, and triple threat photosynthesis strategy weren’t enough to make you love this unique and beautiful plant, here’s one more cool fact.  Snow-on-the-mountain and other spurges produce white milky latex in their leaves and stems just like milkweed plants and rubber trees.  The latex isn’t sap, it’s made by a completely separate production system and doesn’t travel through the plant.  It’s a defense mechanism that is bad tasting and irritating to the skin of many animals (including humans with latex allergies).

Snow-on-the-mountain is a gorgeous native wildflower.  It used to be more commonly planted as an ornamental because of its beauty, but also because it is relatively free of pests and diseases (due in part to its toxic latex).  Unfortunately, because cattle don’t like to eat it and it can be abundant (and very conspicuous) in overgrazed areas of pastures, it has gotten an undeserved reputation as a nasty weed.  Snow-on-the-mountain doesn’t want to take over the world.  It just likes to grow in places where nothing else is growing anyway, and it gives way politely when the neighbors start getting pushy.

Does that sound like an invasive plant to you?  It sounds to me like a plant that needs a friend.  Let’s be friends with snow-on-the-mountain.  What do you say?