Trillium recurvatum

Trillium-time is upon us! This beautiful and uncommon group of plants is perennially interesting and compelling, so let's take a moment to chronicle their brief flowering season. 

As documented previously, the arboretum is home to two species of trillium: Trillium gracile and Trillium recurvatum. In this series of photographs, we are focusing on Trillium recurvatum. The Key to Trillium, provided by the North Carolina Botanical Garden, helps to confirm that the species pictured below is indeed Trillium recurvatum.

In this photo, we see two individual trillium plants. A tall stalk supports a little burgundy flower that has three large mottled green leaves.

Do you see the three wine-colored petals that are standing upwards and meeting? This helps us identify our plant as Trillium recurvatum.

This plant is less than a foot high, approximately 10 inches above the ground.

One petal and two filaments were removed to get a better look at the reproductive parts.

The green sepals curve down, between the mottled green leaves (bracts). These sepals touch the stalk (scape).

There are six filaments. The anther connectives are curved inward.

Filaments are more than ¼ inch in length. The flower does not smell bad; there is a faintly pleasant smell, nothing offensive. Following the Key to Trillium, we can conclude that this is definitely Trillium recurvatum.

Summer Trillium

Trilliums have a rarity and delicate beauty that grant them a wide following among botanical enthusiasts. The four most common species of trillium in Louisiana are T. texanum, T. recurvatum, T. ludovicianum, and T. gracile.

In the arboretum, we have patches marked for T. gracile and T. recurvatum. T. gracile was acquired first, in 1992. Professor Leuck's Plant Systematics class took a field trip down to the Kisatchie National Forest in Natchitoches Parish, and they brought back one T. gracile plant. It was planted in the arboretum, and over the years a patch of trillim developed. Two additional plantings were added to this patch, all thought to be T. gracile: in 1993, Will Cook donated two plants, and in 1994, the Plant Systematics class brought back two more plants from Kisatchie.

In 1994, Jack Price donated T. recurvatum, collected from Caddo Parish. Two years later, another plant from the grounds of the Veterans Affairs Hospital in Shreveport was added to the patch. In 1998, two pots of T. recurvatum origianlly collected from Ida, Louisiana, were then added to the same spot. Finally, in 2013, Professor Leuck donated his own private collection of T. recurvatum to the arboretum, adding them to same location.

Since we haven't closely examined these species on the blog, let's start today, as this week we noticed seeds from a patch marked T. gracile. Have you ever seen trillium seeds? Few people have.

All photos below are of a single patch of trillium, currently labeled as T. gracile. This blog post is meant as a start for close examination of the arboretum's trillium species. It has been three decades since the first planting of trillim into the arboretum, and classification criteria change over time. Plants get moved around, too; a volunteer trillium will pop up in an inhospitable location and need to be relocated to a safe spot. It could very well be the case that we have mixed patches of trillium. Perhaps T. gracile and T. recurvatum have even hybridized! So, we need to see what the trillium specialists have been studying and how these folks have been dividing up the various species. All photos below are from July 2023. These are summer photos and consequently the leaves (bracts) aren't in their best condition.

Here we see one individual trillium. It has three green, floppy leaves elevated off the ground by a stalk. These aren't regular leaves; these are called bracts, and they are part of the trillium reproductive structure. Despite the hot-hot July weather, these bracts are still in fairly good condition. We see that they are mottled and are close together. The bracts surround a ripening seed pod. This individual is showing definite characteristics of T. gracile.

Zooming in on the ripening seed pod, we see that the sepals are partially shielding the pod. Also, note how the seed pod appears to sit on top of the bracts. There isn't a stem separating the seed pod from the bracts. For classification purposes, this type of trillium is called 'sessile.' Both T. gracile and T. recurvatum are sessile.

This is another individual, in the same patch of trillium, and it has a slightly different look. First, it appears more withered: the bracts are yellowing and wrinkling. Second, these bracts are not snuggly whorled around the ripe seed pod; thin, light-green sepals partially curve down between the bracts. This is a characteristic of T. recurvatum. Also, interestingly, our patch of T. recurvatum, located under our native witch-hazel, is completely done for the year―nothing is above ground at this time.

The withering individual was snipped for closer examination.

One sepal is curved down; one sepal is curled on itself; and one sepal is stretched out with a partial downward curve. This description doesn't fall in line with either T. gracile or T. recurvatum. Perhaps it is one of the other many different trillium, such as T. foetidissimum or T. ludovicianum.

Six small seeds were collected and planted in a completely different location. Hopefully something will come up!

 

Next spring, we ought to measure and smell the fresh trillium flowers. Have you ever thought to smell a trillium flower? I hope not. The reviews are less than favorable. In Louisiana, you run the risk of encountering the odor of rotten meat. Yuck! What critter is attracted by this foul stench? Such undesirable tasks as sniffing the flowers will help us carefully classify the trilliums that the arboretum has in its collection. In the interim, check out the "Key to Trillium" from the North Carolina Botantical Garden for all of the different trillium characteristics.

 

From the USDA Forest Service, you can find a little more information about the the four species shown on the above map:

Trillium ludovicianum

Trillium gracile

Trillium recurvatum

Trillium texanum

Trillium recurvatum

Trillium recurvatum is commonly known as "Prairie trillium."