Rare and Endangered Plants: Texas Wild Rice

Some plants have native ranges that are so condensed that a single major disturbance has the potential to wipe them out of existence completely. They are significantly more vulnerable to change than neighboring plant species, and for this reason they often find themselves on endangered species lists. Zizania texana is one of those plants. Its range was never large to begin with, and due to increased human activity it now finds itself on the brink of extinction.

Zizania texana is one of three species of wild rice found in North America. The other two, Z. palustris and Z. aquatica, enjoy much broader ranges. Both of these species were once commonly harvested and eaten by humans. Today, Z. palustris is the most commercially available of the two. Commonly known as Texas wild rice, Z. texana, was not recognized as distinct from the other two Zizania species until 1932.

Herbarium voucher of Texas wild rice (Zizania texana) - photo credit: University of Texas Herbarium

Herbarium voucher of Texas wild rice (Zizania texana) – photo credit: University of Texas Herbarium

Texas wild rice is restricted to the headwaters of the San Marcos River in Central Texas. The river originates from a spring that rises from the Edwards Aquifer. It is a mere 75 miles long, but is home to copious amounts of wildlife, including several rare and endangered species. Before the 1960’s, Texas wild rice was an abundant species found along several miles of the San Marcos River. Its population and range has since been greatly reduced, and the native population is now limited to about 1200 square meters within the first two miles of the river.

Texas wild rice is an aquatic grass with long, broad leaves that remains submerged in the clear, flowing, spring-fed water of the river until it is ready to flower. Flower heads rise above the water, and each flower spike consists of either male or female flowers. The flowers are wind pollinated, but research has revealed that the pollen does not travel far and does not remain viable for very long. If a male flower is further than about 30 inches away from a female flower, the pollen generally fails to reach the stigma. The plants also reproduce asexually by tillering, but plants produced this way are genetically identical to the parent plant.

As people settled in the area around San Marcos Springs and began altering the river for their own use, Texas wild rice had to put up with a series of assaults and dramatic changes, including increased sediment and nutrient loads, variations in water depth and speed, trampling, and mechanical and chemical removal of the plant itself. Sexual reproduction became more difficult. In his book, Enduring Seeds, Gary Paul Nabhan describes one scenario: “streamflow had been increased to the extent that the seedheads, which were formerly raised a yard above the water, [were] now constantly being pummeled by the current so that they [remained] submerged, incapable of sexual reproduction.”

San Marcos, Texas – where the headwaters of the San Marcos River is located and where Texas wild rice has long called its home – is the location of Texas State University and is part of the Greater Austin metropolitan area. Thus, Zizania texana now finds itself confined to a highly urbanized location. The San Marcos Springs and River are regularly used for recreation, which leads to increased sediments, pollution, and trampling. Introduced plant species compete with Texas wild rice, and introduced waterfowl and aquatic rodents consume it. In this new reality, sexual reproduction will remain a major challenge, and a return to its original population size seems veritably impossible.

Texas wild rice (Zizania texana) and its urbanized habitat - photo credit: The Edwards Aquifer

Texas wild rice (Zizania texana) and its urbanized habitat – photo credit: The Edwards Aquifer

Attempts have and are being made to maintain the species in cultivation and to reintroduce it to its original locations, but its habitat has been so drastically altered that it will need constant management and attention for such efforts to be successful. As Nabham puts it, it is a species that has “little left of [its] former self in the wild – it is a surviving species in name more than in behavior…The wildness has been squeezed out of Texas rice.”

What if humans had stayed out of it? Would a plant with such a limited range and such difficulty reproducing sexually persist for any great length of time? It’s hard to say. If it disappears completely, what consequences will there be? It is known to provide habitat for the fountain darter, an endangered species of fish, as well as several other organisms; however, the full extent of its ecological role remains unclear. It will be nursed along by humans for the foreseeable future, but it may never regain its full glory. It is a species teetering on the edge of extinction, simultaneously threatened and cared for by humans – a story shared by so many other species around the world.

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Texas State Flower

The state flower of Texas blooms in early spring. At least most of them do anyway. Some don’t bloom until late spring and others bloom in the summer. The reason for the staggered bloom times is that the state flower of Texas is not one species but six. All are affectionately referred to as bluebonnets and all are revered by Texans.

As the story goes, at the beginning of the 20th century the Texas legislature set out to determine which flower should represent their state. One suggestion was the cotton boll, since cotton was a major agricultural crop at the time. Another suggestion was a cactus flower, because cacti are common in Texas, are long-lived, and have very attractive flowers. A group of Texas women who were part of the National Society of Colonial Dames of America made their pitch for Lupinus subcarnosus, commonly known as buffalo clover or bluebonnet. Ultimately, the nomination from the women’s group won out, and bluebonnets became an official state symbol.

The debate didn’t end there though. Many people thought that the legislature had selected the wrong bluebonnet, and that the state flower should be Lupinus texensis instead. Commonly known as Texas bluebonnet, L. texensis is bigger, bolder, and more abundant than the comparatively diminutive L. subcarnosus. This debate continued for 70 years until finally the legislature decided to solve the issue by including L. texensis “and any other variety of bluebonnet not heretofore recorded” as the state flower of Texas.

Lupinus texensis - Texas bluebonnet

Lupinus texensis (Texas bluebonnet) bravely growing in Idaho

According to Mr. Smarty Plants, the list of Texas state flowers includes (in addition to the two already mentioned)  L. perennis, L. havardii, L. plattensis, and L. concinnus. Most on this list are annuals, and all are in the family Fabaceae – the pea family. Plants in this family are known for their ability to convert atmospheric nitrogen into plant available nitrogen with the help of a soil dwelling bacteria called rhizobia. The genus Lupinus includes over 200 species, most of which are found in North and South America. Others occur in North Africa and the Mediterranean. Plants in this genus are popular in flower gardens, and there are dozens of commercially available hybrids and cultivars.

L. subcarnosus is sometimes referred to as sandy land bluebonnet and occurs mainly in sandy fields and along roadsides. L. texensis is a Texas endemic; its native range includes the prairies and open fields of north and south central Texas. It is now found throughout Texas and bordering states due to heavy roadside plantings. L. perennis is the most widespread Texas bluebonnet, occurring throughout the eastern portion of the U.S. growing in sand hills, woodland clearings, and along roadsides. L. havardii is the largest of the Texas bluebonnets. It has a narrow range, and is found in a variety of soil types.  L. plattensis is a perennial species and occurs in the sandy dunes of the Texas panhandle. L. concinnus is the smallest of the Texas bluebonnets and is found mainly in sandy, desert areas as well as some grasslands.

Lupinus concinnus (...) - photo credit: www.eol.org

Lupinus concinnus (Nipomo Mesa lupine) – photo credit: www.eol.org

A legend surrounds the rare pink bluebonnet.

A legend surrounds the rare pink bluebonnet

Read more about Texas bluebonnets here and here.

“I want us to know our world. If I lived in north Georgia on up through the Appalachians, I would be just as crazy about the mountain laurel as I am about bluebonnets.” – Lady Bird Johnson

Field Trip: Lady Bird Johnson Wildflower Center, part two

This is the second in a series of two posts about my recent trip to Lady Bird Johnson Wildflower Center in Austin, Texas. You can read the first post here. Both posts are comprised of mostly pictures, as they tell a much better story about the place then my words can. However, even pictures don’t do the place justice; it’s definitely a site that you are going to have to see for yourself. I highly recommend it.

One name that kept coming up during the native plant conference was Doug Tallamy – and for good reason. Tallamy has long promoted and encouraged the use of native plants in landscapes, largely for the creation of wildlife habitat in urban and suburban areas. In 2007 he put out a book entitled, Bringing Nature Home: How You Can Sustain Wildlife with Native Plants, in which he made a strong argument for native plant gardens. His book and lectures have inspired many to seek out native plants to include in their yards. What was lacking in his book, however, was detailed information on the horticulture and design aspects of using native plants. So in 2014, together with Rick Darke, Tallamy put out The Living Landscape, an impressive tome outlining how to create beautiful and functional gardens using native plants. Both books are well worth your time.

The plant name following each photo or series of photos links to a corresponding entry in the Native Plant Database which is managed by the Wildflower Center’s Native Plant Information Network. The quotes that accompany the plant names are taken from the Native Plant Database entries.

Ilex vomitoria (yaupon). “The leaves and twigs contain caffeine, and American Indians used them to prepare a tea which they drank in large quantities ceremonially and then vomited back up, lending the plant its species name, vomitoria. The vomiting was self-induced or because of other ingredients added; it doesn’t actually cause vomiting.”

aesculus pava var pava 3

Aesculus pavia var. pavia (red buckeye). “Long popular for its brilliant, hummingbird-attracting spring flowers and rich green foliage, it is found in nature most often as a plant of woodland edges, where it can get morning sun and afternoon shade.”

tillandsia recurvata 5

Tillandsia recurvata (ball moss). An epiphyte commonly found on trees within its range, including Quercus fusiformis (escarpment live oak) a dominant tree at the Wildflower Center. “Some have been introduced into other warm regions and cultivated for use as ornamentals or for their edible fruit.”

Opuntia ellisiana (spineless prickly pear). A spineless form of Opuntia cacanapa derived from cultivation. “The spineless prickly pear is a great addition to the landscape for those seeking a cactus form, showy blooms, and bright red cactus fruits (tunas). Beware, although it doesn’t have long sharp spines, the tiny glochids (slivers) are very irritating to the skin if the plant is not handled correctly.”

Gelsemium sempervirens (Carolina jessamine). “The flowers, leaves, and roots are poisonous and may be lethal to humans and livestock. The species nectar may also be toxic to honeybees if too much is consumed, and honey made from Carolina jessamine nectar may be toxic to humans.”

Lonicera sempervirens (coral honeysuckle). “Flowers attract hummingbirds, bees, and butterflies. Fruits attract quail, purple finch, goldfinch, hermit thrush, and American robin.”

windmill

Field Trip: Lady Bird Johnson Wildflower Center, part one

Last week my place of employment sent me to Austin, Texas to spend some time at the Lady Bird Johnson Wildflower Center. I was there for a native plant conference put on by the American Public Garden Association. I had been wanting to visit the Wildflower Center for a long time, so it was great to finally get the chance. Their gardens are truly amazing. I spent three days there, but could have easily stayed much longer. The native plant conference was great, too. I learned a lot about native plant horticulture, and I left feeling inspired to put those things into practice. If you are wondering “why native plants?,” the Wildflower Center has a good answer to that on their website.

While I was there I took dozens of photos, so I am sharing some of those with you in a two part post. The plant name following each photo or series of photos links to a corresponding entry in the Native Plant Database which is managed by the Wildflower Center’s Native Plant Information Network. The quotes that accompany the plant names are taken from the Native Plant Database entries.

Sophora secundiflora (Texas mountain laurel). “The fragrance of Texas mountain laurel flowers is reminiscent of artificial grape products.”

Ranunculus macranthus (large buttercup). “This is one of the largest flowered native buttercups. The large butter-yellow flowers and attractive foliage of this plant immediately attract the eye.”

echinocereus reichenbachii 3

Echinocereus reichenbachii (lace cactus). “Lace cactus is unpredictable in its development, one plant forming a single stem, while its neighbor may branch out and form a dozen or more.”

Dalea greggii (Gregg’s prairie clover). “Grown mostly for its silvery, blue-green, delicately compound leaves, the shrub is awash with clusters of tiny, pea-shaped, purple flowers in spring and early summer.” 

viburnum rufidulum 5

Viburnum rufidulum (southern blackhaw). “In Manual of the Vascular Plants of Texas, Correll and Johnston noted that the fruit tastes similar to raisins.”

mahonia trifoliata 5

Mahonia trifoliolata (agarita). “Songbirds eat the fruits, and quail and small mammals use the plant for cover. It is considered a good honey source.”

lady bird johnson quote