The arid and semi-arid regions of west and south Texas are most commonly associated with thorny plants, but the Honey Locust (Gleditsia triacanthos) of the East Texas woodlands have thorns unmatched for their size, complexity and magnificent thorniness:
Bexar County is on the western edge of the Honey Locust's native range. The USDA Plants Database indicates these trees are becoming a remnant population in Karnes, Bexar, Medina and Edwards Counties. As remnant populations, they are becoming increasingly separated from larger populations further to the east.
Honey Locust seed pods are of a size proportional to the size of the thorns. They typically grow up to a foot long. The pulp in the ripening pods between the seeds is very sweet, containing up to 30% sugar. These were an important food for Native Americans. Native Americans also used the thorns as tips for fishing spears.
This set of photographs was taken along the Yanaguana Nature Trail at Mission San Juan in the San Antonio Missions National Historical Park on Monday, October 28, 2013.
This is the fourth in a multi-post series. Part 1 is here, Part 2 here and Part 3 here.
The thorny twigs of Bluewood Condailia, Lotebush and Granjeno can be somewhat camouflaged by the leaves growing from them. This is not at all true of Huisache (Acacia farnesiana) thorns. These thorns may not always be easy to see through the foliage, but I'm not sure how they could be any more obvious:
Plants in the Genus Acacia are shrubs or small trees. Almost all of them have thorns, some more obvious than others. Huisace generally grows to be a small to medium sized tree. It is very common from the southern edge of the Texas Hill Country south through the South Texas Brush Country. Huisache blooms late in winter becoming covered with fragrant bright yellow "puffball" flowers.
There are a couple things to keep in mind particularly if Huisache are used as a landscape tree. Huisache thorns have been known to puncture both the soles of shoes and car and truck tires. Also, when trimmed or pruned, the new growth that follows will have larger and more plentiful thorns.
This set of photographs was taken along the Yanaguana Nature Trail at Mission San Juan in the San Antonio Missions National Historical Park on Monday, October, 28, 2013.
This is the third in a multi-post series. Part 1 is here and part 2 here.
The Granjeno, as it is most commonly called in much of South Texas, may be best known for its prominently zigzagged branches. It is also known as a Desert Hackberry. Celtis pallida (yes, it is also known as Palo Blanco) is a close cousin of Sugar Hackberry (Celtis laevigata) and Netleaf Hackberry (Celtis reticulata) and is just as important a plant for wildlife as its two larger cousins.
Unfortunately, another common name for this shrub that has stuck as tight as a thorn through a pant leg is Spiny Hackberry. Remember, spines are modified leaves and thorns are modified branches. If one looks close enough at the Spiny Hackberry, it can easily be seen there are leaves growing from the "spines" much like Bluewood Condalia and Lotebush. These are in fact short twigs with terminal thorns:
The Granjeno grows throughout the South Texas Brush Country and the Big Bend Region of Texas. It is the larval host plant for the American Snout and the Empress Leilia butterflies. Its bright orange berries that ripen in late summer and early fall are another critical food source for migratory birds and other wildlife.
This set of photographs was taken along the Yanaguana Nature Trail at Mission San Juan in the San Antonio Missions National Historical Park on Monday, October 28, 2013
This is the second post in a multi-post series. Part 1 is "A Brief Introduction to a Very Thorny Subject."
We use the word "thorn" very generically to refer to any sharp pointy part of a plant. However, to be technically correct, there are three different types of sharp pointy things:
- Prickles are modified epidermal tissue. The epidermis is the surface layer of the stem. Prickles are found on many plants in the Rosaceae (Rose) Family, as well as other plants such as Greenbrier vine.
- Spines are modified leaf tissue. The sharp pointy things on cacti are spines. The sharp tips of Agarita leaves and the sharp projections along the margin of Sotol leaves are also spines.
- Then there are the true thorns. Thorns are modified branch tissue. They are essentially branches with sharp pointed tips. Numerous trees and shrubs have true thorns.
This is going to be a series of posts. Probably the best place to begin is with the Bluewood Condalia (Condalia hookeri). This Condalia generally grows as an understory shrub in wooded areas of the Texas Hill Country and to the south in the open brush throughout the South Texas Brush Country.
The leaves of Bluewood Condalia grow on twigs with a very sharp terminal thorn. This is by far one of the best examples demonstrating that thorns are in fact modified branches:
Lote-bush Condalia (Ziziphus obtusifolia) looks very similar to Bluewood Condalia and the two are easily confused. Their ranges overlap in Texas. While they are not in the same Genus, they are both in the Rhamnaceae (Buckthorn) Family. Both of these shrubs have leaves on twigs with terminal thorns. The Lotebush, as it is often called, has twigs with leaves as well as bare twigs both with terminal thorns.
This set of photographs was taken along the Yanaguana Nature Trail at Mission San Juan in the San Antonio Missions National Historical Park on Monday, October 28, 2013.
I have to give credit to Dr. Floyd Waller, my botanist friend and mentor, for the original inspiration for this series of posts.
