Vegetation of the Sotol Country. 
Ill 
*Echinocactus williamsii 
Coldenia greggi'i 
*Cactus conimamma 
Coldenia hispidissima 
* Cactus heyderi 
*Lippia ligustrina 
*Cactus micromeris 
Bouchea spathulata 
*Cactus pectinatus 
*Salvia ballotaeflora 
*Cactus pusillus 
*Leucophyllum texanum 
*Cactus scolymoides 
*Leucophyllum minus 
*Cactus viviparus 
Cucurbita foetidissima 
*Cactus williamsii 
Zexmenia brevifoMa 
*Cereus dubius 
Grindelia squarrosa 
*Cereus emory*i 
Eriocarpum rubiginosum 
*Cereus greggii 
*Flourens'ia cernua 
*Cereus longispinus 
Psilostrophe arachnoides 
*Cereus stramineus 
Psilostrophe tagetina 
*Echinocereus caespitosus 
Baileya multiradiata 
*Echinocereus dasyacanthus 
Laphamia angustifolia and others 
*Echinoeereus paucispinus 
Perityle species 
*Ecinoeereus pectinatus 
Bahia species 
*Opuntia arborescens 
Actinella scaposa 
*Opuntia arenaria 
Sartwellia flaveriae 
*Opuntia engelmannia 
Porophyllum species 
*Opuntia leptocauMs 
Chrysactina mexicana 
*Ariocarpus fissuratus 
Ilymenatherum acerosum 
Gaura species 
Hymenatherum greggii and others 
Macrosiphonia berlandieri 
Pectis angustifolia 
Menodora heterophylla 
Pectis longipes 
*Lycium pallidum 
Pectis papposa 
Nama hispidum 
Perezia nana 
Gilia havardi and several others 
Perezia wrightii 
Physalis lobata 
Trixis angustifolia 
Coldenia canescens 
From this list it is to be noted first of all that the dominant 
species have a very general distribution throughout the arid rocky 
plateau embracing Trans-Pecos Texas, Southern New Mexico, 
Arizona, Southeastern California and the Mexican States of So- 
nora, Chihuahua, Coahuila, Nueva Leon and several others imme- 
diately to the southward, and that as a rule these species are not 
found elsewhere outside of this region. Species of the Great 
Plains and of the Pocky Mountains are scarcely represented in the 
formation, although the level plateau above Alpine, Marfa, etc., has 
a characteristic Great Plains flora and the elevated mountain peaks 
possess islands of Rocky Mountain flora. Still less is there any 
representation of the Austro-riparian flora, and comparatively little 
of what is called the Gulf Neotropical (except, perhaps, Porliera, 
Helietta, Amyris, Amoreuxia). 
One the whole, the flora of this arid region is little shared with 
similar regions of other continents, there being more exceptions to 
