Figure 23. Pacific cordgrass in flower. 



Hollow air-filled tissue in the stem carries oxygen from the leaves to 

 roots and rhizomes. This mechanism also introduces oxygen into the 

 soil surrounding the root and rhizome system. It tolerates salt by 

 excreting it through salt glands. 



Two forms of Pacific cordgrass have been identified in San Francisco: 

 a medium, stout form (0.3 to 1.2 meters high), which grows in the lower 

 zone, and a dwarf (0.2 to 0.3 meter high), which occurs mixed with 

 pickleweed at higher elevations (Kasapligil, 1976) . It is not known 

 whether these forms have a genetic basis or are due to environmental 

 features. Short-term field tests (Harvey, 1976) suggest that the two 

 forms react differently to elevation. The dwarf form was able to sur- 

 vive transplanting at a higher elevation than the stout form. 



Reproduction in established stands is vegetative through extensive 

 underground stems (rhizomes). Seed production is erratic and usually 

 limited in old, dense stands. It may be substantial in newly establish- 

 ed stands or along margins. Seeds are important for spreading the plant 

 into new or freshly disturbed areas (Mason, 1976) . 



The capacity of Pacific cordgrass to grow lower in the tidal range 

 than any other marsh species makes it especially valuable in marsh build- 

 ing. It provides downs lope protection and grows where its detritus is 

 readily transferred to the estuary by tidal action. The association of 



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