by spring or storm tides is followed by periods of low rainfall and 

 warm temperatures. Established plants can tolerate this but fresh 

 transplants may be severely damaged. 



c. Pacific Cordgrass . This grass may be propagated vegetatively 

 and by seeds. It has similar but perhaps more exacting propagation 

 requirements than smooth cordgrass. 



(1) Seeds . Seed production in Pacific cordgrass is very er- 

 ratic. Early investigators believed that viable seeds were seldom pro- 

 duced and of minor significance in the spread of this species (Purer, 

 1942; Hinde, 1954). However, recently substantial seed crops (viabili- 

 ty 80 percent) have occurred in the San Francisco Bay area. Seeds from 

 these sites have been harvested and stored, and plants have been produc- 

 ed from them (Mason, 1976). The best seed production was located near 

 bay tributaries. The lower salinities at these sites may be a factor 

 encouraging seed formation although this has not been established. Like 

 smooth cordgrass. Pacific cordgrass seed heads may be attacked by ergot 

 {Clavioeps purpurea) (Fig. 27) (C. Newcombe, Director, San Francisco Bay 



Marine Laboratory, personal communication, 1978) . 



Pacific cordgrass seeds mature in the San Francisco Bay area in 

 October; seed heads begin to shatter shortly thereafter. Harvesting 

 must be timed just before shattering when some seeds are easily dis- 

 lodged by tapping the heads or stalks. Mature heads may be clipped 

 by hand either from a boat or by wading Seeds should be stored in 

 cold saltwater for about 2 weeks to loosen inflorescences. Seeds may 

 then be threshed by placing heads on a No. 30 screen and subjecting them 

 to a strong spray of water from a hose. Viability of seeds has been 

 maintained over winter -by storing in cold (4 Celsius) freshwater or 

 saltwater (11 to 12 parts per thousand). Saltwater is more effective 

 in preventing germination during storage. Satisfactory germination has 

 resulted when seeds were placed in freshwater at the end of the storage 

 period (Mason, 1976) . There is some indication that germination of 

 Pacific cordgrass may be more sensitive to salinity than smooth cord- 

 grass. Viability is not maintained by drying or freezing. 



Plants have been produced from seeds by direct seeding in sand, 

 sand-silt, or vermiculite mixtures in peat pots or by germinating seeds 

 in petri dishes and transplanting to peat pots (Mason, 1976). 



(2) Plants. Four types of Pacific cordgrass transplants have 

 been used successfully in recent trials in the San Francisco Bay area 

 (Knutson, 1975; U. S. Army Engineer District, San Francisco, 1976): 



(a) seedlings grown for 4 months in 10-centimeter peat 

 pots; 



(b) plugs, prepared by removing 13-centimeter cubes con- 

 taining crowns, roots, rhizomes, and soil, from a tall, healthy cord- 

 grass marsh; 



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