12 February 2010

All Clovers Are Not Created Equal

Here in Indiana, clovers (Trifolium spp.) don't get people very excited. I don't think I've ever heard anyone say that a clover of any kind is one of their favorite plants. In fact, these legumes with three leaflets are often shunned as evil lawn weeds, and many a suburban homeowner spend hundreds of dollars per year applying herbicides to remove the clover and cultivate a bluegrass monoculture. Recently, however, there has been a movement to replace or at least enhance turf grass lawns with clovers, which take nitrogen from the atmosphere and make this natural fertilizer available to other plants.

Around here, our most common clovers are Red Clover (Trifolium pratense, above), White Clover (Trifolium repens, below), and Alsike Clover (Trifolium hybridum). While the individual flowers are humbly attractive when viewed up close, most people do not give them a second glance when in their heavily degraded and anthropogenically altered habitats of old field, pasture, roadside, and lawn.

Enter the clovers of Colorado. Never before had I really been "wowed" by a clover, nor did I think I could be, but these fantastic Fabaceae seemed like they were from another world. All three of the following species are native to Colorado and endemic to the Rocky Mountains.

Parry's Clover (Trifolium parryi, above) is a plant found only in a fairly narrow band through the Rocky Mountain states (Southwest Colorado Wildflowers 2010) that can be found growing commonly in the subalpine and alpine life zones (Guennel 2004). This species often grows in dense clumps or cushions with leafless flowering stalks (Beidleman et al. 2000). While the "plainest" looking of the three clovers that we saw on our July 2009 trip, this clover puts all of the Midwestern clovers that I've seen to shame.

The next most impressive clover species that we saw was Alpine Clover (Trifolium dasyphyllum), shown immediately above and below. Like the previous species, Alpine Clover is common in a fairly narrow band through the Rocky Mountain states (Southwest Colorado Wildflowers 2010), found growing in tundra and on rocky or gravelly slopes in the subalpine and alpine life zones (Guennel 2004).

The flowers of Alpine Clover can sometimes be all rose or violet-purple (Southwest Colorado Wildflowers 2010), but the more common bicolored form shown in the photos above is quite stunning, especially for a clover.

Finally, Dwarf Clover (Trifolium nanum), which puts all other clovers to shame in terms of appearance, in my opinion, is shown above. Another species of restricted range similar to the previous two species (Southwest Colorado Wildflowers 2010), this clover has only 1-3 flowers per cluster; each flower is approximately 2 cm long, but the entire plant lives up to its common name and grows in a cushion up to only 6 cm tall (Beidleman et al. 2000). Dwarf Clover is found in meadows, on gravelly slopes, and on rocky ridges in the subalpine and alpine life zones (Guennel 2004).

Beidleman, L.H., R.G. Beidleman, & B.E. Willard. (2000). Plants of Rocky Mountain National Park. Estes Park, Colorado: Rocky Mountain Nature Association; Helena, Montana: Falcoln Publishing, Inc.

Guennel, G.K. (2004). Guide to Colorado Wildflowers, Volume 2: Mountains. Englewood, Colorado: Westcliffe Publishers.

Southwest Colorado Wildflowers. Retrieved February 12, 2010. http://www.swcoloradowildflowers.com/.


Justin Thomas said...

Those sure weren't some sweet clovers. Get it.... "Sweet Clover" (genus Melilotus). In all seriousness, this post changed my perception of Trifolium from "weed everywhere" to "relevant native somewhere". I might add that we do have at least two native species here in the Midwest that are kinda cool.

Scott Namestnik said...

Ha! Funny guy!

I'm guessing the native clovers you are speaking of are T. stoloniferum and T. reflexum. I've never seen either, but from what I've seen in photos, these both look a lot like T. repens. Gotta admit, though, I would be pretty excited to see either of these natives.