Vegetation of the Sotol Country. 
109 
ing terraces of gravel or coarser debris about the flat basins or 
bolsons, and on points jutting out into these, and finally upon all of 
that part of the South Plateau where the Cretaceous formation has 
been dissected into an area of high, round topped hills and deep 
canyon fissures, of broad divides and proportionately wide, shal- 
low draws, and of narrow ridges and deeper valleys — everywhere, 
that is, where there is unlevel territory covered by the fragmented 
debris of the disintegrating strata. While this debris- is mostly 
from the disintegrating limestone the sotol formation is by no 
.means limited to limestone but occurs upon other kinds of debris 
where these offer substantially the same physical conditions. 
THE F LORI STIC CONTENT AND RELATIONSHIPS. 
A complete collection and determination of the flora has not 
been made from the sotol formation at any point. The. vicinity 
of Langtry on the Eio Grande not far from the Pecos canyon, and 
points east and west of this have furnished most of the writer’s 
notes and collections. These collections, together with excursions 
to other points in Trans-Pecos Texas where the formation is en- 
tered, and the collections of previous explorers have yielded a suf- 
ficiently representative list to satisfy the objects of the j. resent 
paper. No consideration is given here to species of the canyons 
or other moisture favored situations. 
In the following list, those plants which form the permanent and 
distinctive feattires of the vegetation are starred (*). 
Elionurus barbieulmis 
Elionurus ciliaris 
Hilaria cenchroides 
Hilaria jamesi'i 
Hilaria mutica 
Bouteloua hirta 
Bouteloua oligostachya 
Bouteloua uniflora 
Papphorum wright'ii 
Cathestecum erectum 
Eriochloa punctata 
Aristida bromoides 
Aristida dispersa 
Aristida pupurea 
and others. 
Stipa species. 
Sporobolus confusus 
and others. 
Muhlenbergia arenicola 
Muhlenbergia berlandieri 
Muhlenbergia monticola 
Muhlenbergia texana 
Bouteloua aristidoides 
Bouteloua breviseta 
Bouteloua eriopoda 
Bouteloua havardi 
Tricuspis acuminata 
Poa bigelovii 
Selaginella lepidophylla 
*Ephedra antisyphilitica 
^Ephedra nevadensis 
*Ephedra torreyana 
*Hechtia texensis 
*Yucca constricta 
*Yucca macrocarpa 
*Yucca radiosa 
*Yucca treculeana 
*Samuela faxoniana 
*Hesperaloe parv*iflora 
*Nolina erumpens 
*Nolina lindheimeriana 
*Nolina texana 
