PREFACE. 5 



eeae, Boraginaceae, Scrophulariaceae and Compositae. Some of the most 

 dominant plants are Eschscholtzia californica, Trifolium trident atum, microdon 

 and columbinum, Lupinus affinis, nanus, micranthus and microcarpus, Gilia 

 achillaeafolia and tricolor, Nemophila menziesii, Phacelia tanacetifolia, Allo- 

 carya stipitata and californica, Amsinckia intermedia, Orthocarpus purpur- 

 ascens, erianthus and lithospermoides, Microseris douglasii and elegans, Baeria 

 fremontii and Achyrachaena mollis. 



Alkaline areas of the plains, whether very limited spots or extensive plains, 

 have their own peculiar species. The most abundant and widely distributed 

 in our region are Distichlis spicata, Nitrophila occidentalis, Atriplex bracteosa, 

 Astragalus tener, Sida hederae'ea, Peucedanum caruifolium, Cressa cretica and 

 ]!a> ria platycarpha. 



Scattered over the plain of the valley floor the traveler finds small depressions 

 a few yards square and a few inches deep which fill with water in the rainy 

 season. When such pools are a little deeper, well-defined and numerous, they 

 take the name of "hog wallows." The beds of these pools iu late spring 

 or early summer give rise to a distinctive flora composed of such species as 

 Lilaea subulata, Downingia elegans and pulcJiella, Mimulus bicolor, Boisduvalia 

 cleistogama and glabella var. campestris, Lepidium hit i pes, Gilia leucocephala 

 and Psilocarphus brevissimus. They are diminutive or dwarfish plants with 

 small or narrow leaves. 



The fall flora of the valley plains is represented by great colonies of a 

 comparatively few species. The most important species are Eremocarpas seti- 

 gerus, Grindelia camporum and more especially the various tarweeds such as 

 tiemizonia luzulaefolia, virgata and kelloggh, and Centromadia pungens and 

 fitchii. 



The last important feature of our flora needing mention are the salt marshes 

 about San Francisco, San Pablo and Suisun bays, which support a formation of 

 rushes, sedges and allied plants, rather varied in species and usually very 

 strong in individuals. 



The flora of western middle California, thus so briefly sketched, has been 

 and is still being rapidly modified by the occupations of man. Many species 

 which were once common are now less common or rare. Changes induced in 

 the native plant population by civilization are not, however, always adverse 

 to a species. Some species find improved conditions of existence under civiliza- 

 tion. Phacelia tanacetifolia and Tropidocarpum gracile flourish in grain 

 fields, and Montia gypsophiloides and Calandrinia caulescens var. mensiesii 

 (if this latter be a native plant) thrive and perfect their seeds in orchards and 

 vineyards in the rainy period that just precedes the spring cultivation. In 

 valley lands Calochortus uniflorus is materially assisted in its habits of vogeta- 

 ropogation by the disturbance of the soil in plowing and the consequent 

 separation and scattering of its bulblets. 



On the other hand ali<-n>. especially from the Mediterranean region, are 



--tally and surely Invading extensive tracts and dispossessing the natives. 



Species of this type, introduced in later days, are Picris echioides and ('* n- 



taurea calcitrapa and solstitialis. Tin- progress of these and other plants are 



deserving of the attention of all local botanists interested in the native flora, 



