California Sycamore {Platanus racemosa), California Boxelder 

 (Acernegundo subsp. califomicum), and Fremont Cottonwood 

 (Populus fremontii), along with a number of species of willows 

 (Salix spp.). Where river valleys are broad, the extent of the Rip- 

 arian Woodland is often correspondingly broad; in other areas, 

 particularly at higher elevations where the water courses are nar- 

 row and the streambanks are relatively steep. Riparian Wood- 

 land may form a very narrow strip of forest that is only a few 

 meters in width. The distribution of this plant community has 

 not been included on the map of Woodlands, but it can be plot- 

 ted easily on a map that shows the occurrence of year-round 

 rivers and streams in the state. 



Freshwater Marsh (Plate 11 A; Map 2) 



In areas of the state where there are fairly large expanses of 

 standing or very sluggishly moving, shallow water, one generally 

 encounters the Freshwater Marsh plant community. Floristically, 

 this plant community is a relatively simple one whose main com- 

 ponents are various species of cattails (Typha spp., Typhaceae), 

 bulrush or tule (Scirpus spp., Cyperaceae), and sedges (Carex spp., 

 Cyperaceae). Freshwater Marsh occurs in the Central Valley 

 along river courses, creeks, and sloughs, or in the vicinity of 

 lakes such as Tulare Lake; extensive marshes also occur in the 

 Sacramento-San Joaquin delta area. Marshlands are present in 

 some inland areas such as Sierra Valley north of Lake Tahoe and 

 in the Modoc Plateau area east of the Sierra-Cascade axis. 



The characteristic plant species of the Freshwater Marsh plant 

 community are mostly monocots with a superficial grasslike 

 appearance. Nearly all of the species are perennials that have ex- 

 cellent means of vegetative propagation. One immigrant cattail 

 in a marshy area can occupy many square meters of marsh in a 

 rather short period of time due to rapid vegetative increase, and 

 in many areas of the state open waterways may become clogged 

 by the masses of plants resulting from this growth. 



Accounts of early 19th century explorers in the Central Valley 

 indicate the great difficulty that these people had in getting 

 their horses across the valley because of the marshlands. Thomas 

 Coulter, an Irish physician and botanist who visited California in 



100 



