Wednesday,
March 14 – Northern Big Bend National Park
Andy “Sex Machine” Gerschutz
Molly “Maiden Molly” Nixon
The day is sunny and hot. It rained the night before.
Bottom Top
N 29° 16.465’ N 29° 16.024’
W 103° 17.209’ W 103° 16.001’
5770 ft 6879 ft
[Map]
This trail starts in the mountain basin in a mixed oak woodland on the N-facing slopes and winds up through open pine scrub on the S-facing slopes to eventually peak at an open pine woodland.
The beginning of the trail is N-facing and approximately 20-25°. There are many species of oaks mixed with juniper and mountain mahogany in the low canopy. The shrubs consist of opuntia cacti, sotol, and beargrass. The herb layer is dominated by aristida sp. and has few annuals.
N-facing, lower elevation
slope Cover value
Pinus sembroides 5
Aristida sp. 4
Dasylirion leiophyllum 3
Juniperus deppeana var. deppeana 3
Juniperus flaccida var. flaccida 3
Nolina erumpens 3
Quercus gravesii 3
Quercus griesea 3
Agave havardiana 2
Cheilanthes sp. 2
Gymnosperma glutinosum 2
Opuntia englemannii 2
Quercus emoryi 2
Cercocarpus montanus 1
Corydalis curvisiliqua 1
Descurainia pinnata 1
Eriogonum sp. 1
Quercus hypoleucoides 1
Quercus sp. 1
Rhus trilobata 1
Rhus virens 1
Symphoricarpos rotundifolius 1
Basal rosette purple crucifer 1
Larger white crucifer 1
The south-facing, higher elevation slope is steeper and much more open. Most of the trees fall out and are replaced by cacti and agave. The effect of aspect is very noticeable on the surrounding ridges.
Agave lechuguilla 4
Opuntia chisosensis 3
Oenothera sp. 2
Echinocactus horizonthal 1
Echinocereus enneacanthus 1
Fouquieria splendens 1
Mammalaria heyderi 1
Verbena bipinnatifida 1
The top is very open pine and grass woodland, changing to exposed granite.
Bromus sp.
In the valleys, disjunct populations of Pinus arizonica can be seen. These are remnants from when the climate was more similar to the rocky mountains.
Location: N 29° 20.332’ W 103° 11.874’
Elevation: 3615 ft.
We stopped on the road just north of the main visitor center. The terrain is extremely flat and open. Desert annuals dominate here.
Agave lechuguilla 5
Dyssodia pentachaeta 5
Lupinus havardii 5
Gymnosperma glutinosum 4
Larrea tridentata 4
Lepidium sp. 4
Nerisyrenia camporum 4
Opuntia englemannii 2
Opuntia macrocentra 1
Phacelia sp. 1
Cane cholla 1
Stop 14-3: Purple Larrea flats
Location: N 29° 26.551’ W 103° 08.266’
Elevation: 2886 ft.
[Photo - Macaranthera dominates clayey Larrea flats]
Flat on road on way Dagger Flats. Dominated by annuals.
Dyssodia pentachaeta 5
Larrea tridentata 5
Macarantha tanacetifolia 5
Lesquerella sp. 4
Baileya multiradiata 3
Nerisyrenia camporum 3
Nama hispidum 1
Sphaeralcea angustifolia 1
Lupinus havardii (dominant
on roadside)
Pencil cholla 1
Location: N 29° 31.514’ W 103° 02.958’ [Map]
Elevation: 3558 ft.
[Photo - Yucca faxoniana at Dagger Flats]
Valley filled with many types of yucca, including the tall Y.
faxoniana
In valley:
Dasylirion leiophyllum 6
Agave lechuguilla 5
Bouteloua sp 5
Diasperus texana 5
Yucca faxoniana (=carnerosana) 5
Yucca torreyi 4
Yucca thompsoniana 3
Dyssodia pentachaeta 2
Ephedra sp. 2
Erysimum sp 2
Larrea tridentata 2
Nerisyrenia camporum 2
Ariocarpus fissuratus 1
Berberus trifoliata 1
Common white crucifer 1
Echinocactus horizonthal 1
Echinocereus chloranthus 1
Fouquieria splendens 1
Lepidium sp. 1
Linum rigidum 1
Lycium sp. 1
Nama hispidum 1
Oenothera sp. (yellow flower, entire leaves) 1
Opuntia leptocaulis 1
Opuntia macrocentra 1
Prosopis glandulosa 1
Senna wislizeni 1
Quincula lobata 1
Juniperus pinchotii ?
On the ridge, much more exposed
Resurrection fern 2
White composite with yellow disk 2
Castilleja lanata 1
Coryphantha cornifera var. echinus 1
Coryphantha dasyacantha var. varicolor 1
Dalea formosa 1
Galium sp. 1
Gilia rigidula 1 (locally abundant)
Melampodium leucanthum 1
Mimosa sp. 1
Notholaena sinuata 1
Location: N 29° 29.492’ W 103° 04.243’ [Map]
Elevation: 3420 ft.
Black igneous outcrop, on the road from dagger flats. Approximately 15° slope, mostly cacti, a lot of exposed rock. There is a limestone cap on the igneous exposure and as you move up the slope, the cover increases. The top of the limestone cap is very different in species composition from the igneous exposure at the bottom of the slope.
Nama hispidum 5
Dyssodia pentachaeta 4
Larrea tridentata 4
Notholaena sinuata 4
Echinocereus enneacanthus var.
dubius 2
Lepidium sp. 2
Lupinus havardii 2
Yucca torreyi 2
Baileya multiradiata 1
Christmas cholla 1
Dalea formosa 1
Ephedra sp. 1
Fouquieria splendens 1
Glandulacactus uncinatus var.
wrightii 1
Guaiacum angustifolium 1
Gymnosperma glutinosum 1
Lesquerella purpurea 1
Opuntia chisosensis 1
Opuntia macrocentra 1
Opuntia rufida 1
On the top of the limestone cap: We walked onto the ridge at the top of the valley and were able to see the Dyssodia pentachaeta in stripes on the surrounding slopes. The working hypothesis was that the distribution was controlled by calcium (limestone). In the valley below the Nama appeared concentrated behind barchans, thereby suggesting a new wind-based theory of annual distribution..
Agave lechuguilla 5
Bouteloua sp. 5
Dyssodia pentachaeta 4
Larrea tridentata 4
Streptanthus carinatus 4
Fouquieria splendens 3
Lepidium sp. 3
Linum rigidum 3
Opuntia englemannii 3
Ephedra sp. 2
Nama hispidum 2
Nerisyrenia camporum 2
Opuntia rufida 2
Baileya multiradiata 1
Christmas cholla 1
Croton fruticulosus 1
Echinocactus horizonthal 1
Echinocereus enneacanthus var. dubius 1
Glandulacactus uncinatus var. wrightii 1
Location: N 29° 24.630’ W 13° 12.457’ [Map]
Elevation: 3295 ft.
On the road we saw Ungnadia speciosa (1) in the washes. The hike was up a dry creek bed surrounded by igneous slopes on either sides and eventually up onto the exposed igneous slope. We did not take cover values for this hike.
Agave lechuguilla
Baileya multiradiata
Bouteloua sp.
Chamaesaracha villosa
Dalea formosa
Descurainia pinnata
Diasperus texana
Dyssodia sp.
Ephedra sp.
Fouquieria splendens
Guara coccinea (not on species list)
Gymnosperma glutinosum
Larrea tridentata
Lepidium sp.
Lesquerella purpurea
Lupinus havardii
Macarantha tanacetifolia
Nama hispidum
Nerisyrenia camporum
Opuntia englemannii
Opuntia rufida
Phacelia sp.
Plantago helleri
Yucca torreyi
The higher slopes had:
Agave lechuguilla
Baileya multiradiata
Boutelou sp.
Dalea formosa
Dasylirion leiophyllum
Deschrainia pinnata
Dyssodia pentachaeta
Echinocereus enneacanthus var.
dubuis
Ephedra sp.
Fishhook cactus
Fouquieria splendens
Fraxinus cupsidada
Lepidium sp.
Lesquerella purpurea
Nicotiana trigonophylla
Opuntia englesmannii
Opuntia rufida
Phacelia crendulata
Phacelia integrifolia
Resurrection fern
Rhus virens
Yucca carnerosana
Yucca thompsoni