Saturday, March 10 – The Rio Grande Valley

David “Skeeter” Vandermast

Botanist and Hacker

 

After a breakfast in which most of our meals ended with the word “slam”, we traveled west on Rte 90 towards the Edwards Plateau and central Texas.  Within a half hour of leaving San Antonio we began to see bluebonnets and other wildflowers blooming in the road median.  Our appreciation for these flowers was great but little did we know they were but a teaser for the bounty of new plants we would see later.  So abundant and species rich was the desert that Jason claimed to be “freaking out”, possibly considering the implications of what he saw for the application of the hump-back model of species diversity.  Jason thereby earned himself the nickname “Freak Daddy”.  Plants we saw along the way included:

 

Stop 10-1:  Dunlay Texas roadside

Location: N29º20.59’ W99º05.99’

Site:  Grassy road verge

 

Lupinus texensis                                  Tillandsia recurvata

Phoradendron sp.                               Prosopis sp.

 

 
Stop 10-2: Sabinal River roadside

Location: N29º16.05’ W100º15.25’

Site:  Low woods along the Sabinal River in a landscape where woods were confined to concavities I the landscape.  Quercus emoryi was the canopy dominated in the well-grazed riparian woodland

 

Allium sp.                                            Vicia leavenworthii

Acacia tortuosa                                   Corydalis aurea var. occidentalis

Yucca torreyii                                      Quercus emoryi

Ulmus crassifolia                                Verbena goodingii

Castilleja sevillaflora

 

 

Stop 10-3:  Amistad National Recreation Area

Location: N29º28’ W100º 01’

Site:    (A) Overgrazed rocky hilltop overlooking Amistad Lake [MAP]

            (B)  Rocky desert Ridge with well-developed Chihuahuan scrub [MAP]

 

At Del Rio, TX we turned north, taking Rte 277/377 towards the east entrance to Amistad National Recreation Area.  Our side trip was botanically disappointing but we did see a large hawk whose species was a mystery.  We returned to Rte 50, heading west.  We crossed Amistad Reservoir and not long afterwards found a side road to travel down where we could get closer to vegetation that was looking more xerophytic by the mile.  A short distance down the road we pulled over and jumped out of the vans anxious to get a look at unfamiliar vegetation.  At this stop we were introduced to the diversity of cacti we would see throughout our journey.  The family Cactaceae is represented by seven genera in south Texas (Acanthocereus, Echinocactus, Echinocereus,Lophophora, Mammilaria, Opuntia, and Wilcoxia).  Many of the cacti are small and were often in bloom during our time in the desert.  The combination of small and pretty cacti caused Andrea to repeatedly “squeak” about how cute they were.  Although we were seeing new plants for the first time we either forgot to make it an official botanizing stop or the recorder (me) was lax in his duties because there doesn’t seem to be an official list of plant species or UTM coordinates for this location.

 

As we returned to the vans, Dane noticed a Mesquite (Prosopis sp) thorn protruding from the front passenger side tire of the white whale.  He thought to himself “hmm, that doesn’t look good”, and proceeded to pull the thorn from the tire.  A faint but audible hissing noise immediately emanated from the tire.  We beat a hasty retreat to Del Rio to plug the leak.

 

 

Stop 10-4:  Pecos River Bridge Overlook

Location: N29º42.16’  W101º21.11’

Site:  Immediately west of the roadside picnic area.  Chihuahuan well-developed desert scrub.

[Map] [Photo]

 

While in Del Rio it was decided that we would drive west to where Rte 50 crossed the Pecos River and have lunch there.  We stopped at a roadside picnic area overlooking a canyon along the Pecos.  Although I was asleep when we pulled in and didn’t see a sign, I believe we were in an outlying portion of the Amistad National Recreation Area immediately west of the Seminole Canyon State Historic Park.  The overlook was impressive; steep canyon walls fell several hundred feet to the Pecos River below.  Goats grazed on a wide riparian wash across the river.  Even from where we stood it was easy to see that the riparian area along this stretch of river was wholly changed by grazing.  The entire area was covered in short, cropped grass, not a shrub or seedling was in evidence.

 

 

On the canyon walls around us abundant vegetation grew, some of it characteristic of the Chihuahua Desert:

 

Oxalis (at least 2 species)                     Tradescantia sp.

Myosotis sp.                                        Notholaena sinuata

Geranium sp.                                      Anemone heterophylla

Oenothera sp.                                      Phacelia fimbriata

Fouquieria splendens                          Agave lechuguilla

Opuntia leptocaulis                             Jatropa dioica

Ranunculus sp.                                    Dalea gregii

Selaginella lepidophylla                      Selaginella wrightii

Delphinium carolinianum                   Lantana macrophylla

Linum puberulum                                Linum rigidum var. berlanderi

Galium sp.                                           Phacelia congesta

Nama havardii                                    Croton dioica

Dasylirion leiophyllum                        Acacia berlanderi

Plantago rhodosperma                       Pellaea sagitatta

 

In the desert it’s been said, everything pricks, sticks or bites.  Intuitively it seems that observation should refer only to the fauna and flora, but desert rock also seems to obey the aphorism.  Jessica “Scratch” Kaplan learned this when she failed to maintain the OSHA-recommended distance between a boulder and her nose while climbing back to the parking lot. 

 

The desert offers a multitude of ironies for the visitor: one must walk carefully so as to avoid running into things that might draw blood, yet one must also try to avoid stepping on fragile annual wildflowers that may only bloom once every few years.  A place that appears so barren, and in fact is of relatively low diversity most of the time, can be so rich and diverse after a wet winter.  Large, water-demanding Pecan (Carya illinoiensis) plantations are grown here too, by irrigating the trees with irreplaceable aquifer water.  There are other better-suited places to grow Pecans: the Mississippi River valley for instance, where Pecans are native and water is less limiting.  And in the greatest irony of all, the member of our group who was most vocal about the need to step carefully around the fragile desert annuals was the only person to step on a lizard.  Because this person was disconsolate over the accident, I’ve resolved to protect his identity.  Fortunately “Dale” (not his real name) is a vegan and weighs less than the average regional Flora so the lizard was merely stunned and rapidly became frisky in Pat’s magical hands.

 

Having a vegan on the trip was educational for several reasons, not the least of which was the introduction of many of us to Textured Vegetable Protein (TVP).  During the week before spring break Bill Schlesinger introduced methanogenesis to his Biogeochemistry class discussing how it occurred in anoxic soils and in the mammalian gut.  One evening I found myself considering in detail the methanogenesis occurring in the guts in my tent-mates and I after meal of TVP-based chili.  If I ace the methanogenesis question on our next test I owe it all to Dale…er, Dane.  I can state from personal experience that methanogenesis by TVP results in voluminous gas production.  If the world populace were to become vegan and consume TVP daily, global carbon budgets would have to be revised.

 

 

On the road again …

 

The canyon rim above the Pecos River was our last official stop of the day.  If any drive-by botanizing was done on the road after we departed it went unnoticed by the recorder who was sound asleep in the back of Homeslice.  We arrived at our destination, the Marathon Motel in Marathon, TX in the late afternoon.  From our departure from Chapel Hill to our arrival in Marathon the trip had taken approximately 36 hours.  Subtracting out the time we spent botanizing between San Antonio and Marathon we could have made it in 31 hours.

 

After checking in to our rooms and showering we went for dinner at the local singing cowboy restaurant, The Magical Bean.  The proprietor, who also served as host and waiter, was an interesting guy with entertaining stories and songs that were lost on the weary travelers who populated every seat in his small restaurant.  Other than his mention of appearing on the David Letterman show and meeting one of the recent Presidents, I don’t recall much of what he said.

 

 

 

 

After returning to the motel many of us made requisite calls to significant others and then tumbled into bed.  Except for some early morning snoring by one of my roommates, (I’ll call him “Randy” to protect his identity) the night was restful.  The next day we awoke early and ate a breakfast of bagels, peanut butter, and coffee from food we had in the vans.   The hot coffee was welcome in the chill of the morning.  Overnight, frost had accumulated on van windows.  Daily temperatures fluctuate a lot in the desert, especially on cloudless nights.  As a group we were prepared for cold temperatures, most of us brought coats or fleece jackets to wear after the sun went down.  Befitting a member of SCA, Laura brought a cloak to keep her warm.  In retrospect, a modern botanist wearing a medieval-looking cloak in the Chihuahuan Desert was in and of itself an anachronism.  It was a fashion statement probably not seen in that part of the country since the time of the Spanish conquistadors.