Sunday, May 15, 2011

An unusual "quadrillium"

A standout in a family of stunning plants, a gorgeous painted trillium, Trillium undulatum, glistens from a shady copse. A recent expedition into some high Appalachian mountains in southern West Virginia netted many interesting finds, including this species of trillium. If you live in Ohio, good luck finding painted trillium. It barely nips into the extreme northeastern corner of the state, and its endangered status in Ohio is warranted. Venture into the mountains of the Mountaineer State and painted trillium can be frequent in some areas.

The genus name Trillium stems from the latin tres, which means three. An apropos name indeed, as most trilliums come completely assembled in groups of threes: leaves, sepals, petals.

But few rules are hard and fast, and trilliums are known for breaking their normal mathematical code of tres. I was delighted to stumble into a small number of these four-petaled painted trilliums, growing amidst a colony of normal plants. While such "quadrilliums" are certainly not unknown, it was the first time I had seen such an aberration in this species. Finding a four-petaled trillium might be considered equivalent to finding a four-leaved clover.


A typical trillium has three leaves, three petals, and three sepals (pointed leaflike parts subtending the flower and projecting between the petals). There are also three styles - the little filaments projecting from the summit of the ovary in the center of the flower. The small oblong projections surrounding the ovary are the stamens, and there are six ( a doubling of the normal rule of three). This is a typical painted trillium flower, and this scheme holds true for most of the other trilliums.


Here's a closeup of our oddball painted trillium. An anomaly of chromosomes (probably) has shifted this plant from an odd to even formula. There are four petals and four sepals. The sexual parts have been doubled: six styles, and eight stamens. Curiously, the number of leaves remained at three, unless there was a fourth tiny rudimentary leaf that I didn't see.


Such a trillium, while a treat to encounter, is hardly unknown. In fact, this form even has a name: Trillium undulatum forma polymerum. Polymerum means with many members, and refers to the excess parts. Some individuals of this form can have everything in allotments of eight, and I suspect such plants are even more bizarre in appearance than this one is.

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3 comments:

A.L. Gibson said...

Absolutely fantastic, Jim! This is the last of the Ohio indigenous Trillium I need to see and the four-petaled specimen is mind blowingly gorgeous! Glad you all had a great time birding and botanizing in WV!

Michael Bartneck said...

That's a really cool specimen. mycoplasma like bacteria have been shown to produce double flowered forms and color variants in t.grandiflorum , perhaps the same is true for the painted. Either way its rare and beautiful and congrats on finding it.

Wally said...

Funny you should say that, Michael. I came in here to say that I once found a T. grandiflorum with six petals that was infected with mycoplasma.