OVERGRAZING. 



303 



Aristida bromoides. 

 Bouteloua aristidoides. 

 Bouteloua polystachya. 

 Boerhavia torreyana. 

 Boerhavia intermedia. 

 Kallstroemia grandiflora. 

 Kallstroemia parviflora. 



Plantago fastigiata. 

 Eschscholtzia mexicana. 

 Lesquerella gordoni. 

 Lepidium lasiocarpum. 

 Pterocarya linearis. 

 Bowlesia lobata. 

 Plagiobothrys arizonicus. 

 Amsinckia tessellata. 

 Sophia pinnata. 



Summer Annuals. 



Kallstroemia brachystylis. 

 Kallstroemia hirsutissima. 

 Cladothrix lanuginosa. 

 Croton corymbulosus. 

 Solanum elaeagnifolium. 

 Tribulus terrestris. 

 Portulaca oleracea. 



Winter Annuals. 



Daucus pusillus. 

 Erodium cicutarium. 

 Erodium texanum. 

 Phacelia distans. 

 Phacelia crenulata. 

 Lupinus sparsiflorus. 

 Thelypodium lasiophyllum. 

 Thysanocarpus curvipes. 

 Lotus humistratus. 



Haplopappus gracilis. 

 Eriogonum abertianum. 

 Eriogonum polycladum. 

 Pectis angustifolia. 

 Pectis prostrata. 

 Chloris elegans. 

 Eragrostis pilosa. 



Malacothrix sonchoides. 

 Malacothrix fendleri. 

 Oenothera primaveris. 

 Calandrinia menziesii. 

 Baeria gracilis. 

 Lappula texana. 

 Festuca octoflora. 

 Gilia gracilis. 

 Salvia columbariae. 



Bunch-grass prairie indicators. — The most remarkable development of 

 annual indicators of overgrazing has taken place in California. This is un- 

 doubtedly a consequence of its early settlement, together with its mild cli- 

 mate and winter rainfall. In addition to a large number of summer and winter 

 annuals derived from the native vegetation, the most widespread and typical 

 indicators are European weeds, which are nearly all grasses. Many of these 

 were probably introduced from Europe during the period of Spanish occupa- 

 tion, and spread rapidly as a result of overgrazing and fire. These agencies 

 would have first brought about the replacement of the native Stipas, but 

 sooner or later fire and clearing would have caused weeds to spread through 

 much of the chaparral as well. This problem of successive invasions and 

 replacements is now under investigation by means of permanent protected 

 quadrats. Meanwhile, the conclusions reached by Davy (1902:38) afford 

 the best summary of the probable course of development (plate 79) : 



"1. The primitive forage plants were the 'bunch-grasses' (Danthonias, 

 Stipas, Melicas, Poas and perennial Festucas), with annual and perennial 

 clovers, wild-pea vines and wild sunflowers; these were much more abundant 

 in former times than now, and on account of their palatableness they largely 

 disappeared with overstocking. 



"2. With the advent of white settlers and their domestic animals, wild 

 oats (Avenafatua) and alfilerilla (Erodium cicutarium) took possession of the 

 country; these increased in relative abundance as the native forage plants 

 became scarce ; as the latter diminished in quantity, the cattle took to eating 

 the former until they in like manner succumbed, while other plants took their 

 place. 



"3. Small barley grass (Hordeum maritimum gussoneanum) , squirrel tail 

 (Festuca myurus), and soft chess (Bromus hordeaceus) were among the next 

 weedy introductions; the two former, when in a maturing condition being 

 disliked by cattle, have had a chance to spread and cover the ranges; but 

 cattle having acquired a taste for soft chess, it is being kept in check, if not 

 diminishing, on closely grazed ranges. 



"4. A third immigration is now taking place, in which musky alfilerilla 

 (Erodium moschatum), broncho grass (Bromus maximus gussoni), barley grass 

 (Hordeum murinum, locally called fox-tail), tacalote (Centaurea melitensis), 

 hawkbit (Hypochaeris glabra), bur-clover (Medicago denticulata) , and other 



