Spartina foliosa
Spartina alterniflora
California cord grass, Pacific cordgrass
Atlantic cordgrass, salt marsh cordgrass, salt-water cord grass, smooth cordgrass, spartine alterniflore
to 150 cm tall, to 10 mm thick, erect, terete, solitary or in small clumps, succulent, glabrous, often with adventitious roots from the lower nodes, having an unpleasant, sulphurous odor when fresh.
to 250 cm tall, (0.3)5-15(20) mm thick, erect, solitary or in small clumps, succulent, glabrous, having an unpleasant, sulphurous odor when fresh.
mostly glabrous, throats sparsely pilose, lower sheaths sometimes somewhat wrinkled;
ligules 1-2 mm;
blades 8-12 mm wide, flat to loosely involute, glabrous, margins usually smooth, sometimes slightly scabrous, apices acuminate.
mostly glabrous, throat glabrous or minutely pilose, lower sheaths often wrinkled;
ligules 1-2 mm;
blades to 60 cm long, 3-25 mm wide, lower blades shorter than those above, usually flat basally, becoming involute distally, abaxial surfaces glabrous, adaxial surfaces glabrous or sparsely pilose, margins usually smooth, sometimes slightly scabrous, apices attenuate.
12-25 cm, with 3-25 branches, smoothly cylindrical, often partially enclosed in the uppermost sheath;
rachises twisted, glabrous;
branches 2-8 cm, usually closely appressed and twisted, lower branches noticeably longer and less closely imbricate than the upper branches, all branches with axes rarely extending past the distal spikelets, with 8-30 spikelets.
10-40 cm, with 3-25 branches, often partially enclosed in the uppermost sheath;
branches 5-15 cm, loosely appressed, not twisted, more or less equally subremote to moderately imbricate throughout the panicle, axes often prolonged beyond the distal spikelets, with 10-30 spikelets.
8-25 mm, usually appressed, often appearing twisted, those on the lower branches usually less closely imbricate than those on the upper branches.
8-14 mm, straight, usually divergent, more or less equally imbricate on all the branches.
usually curved, sides and keels glabrous, scabrous, or hispid, apices acuminate to obtuse or rounded;
lower glumes 6-12 mm;
upper glumes 8-25 mm, 1-veined;
lemmas glabrous or sparsely appressed pubescent on the sides, keels glabrous, apices obtuse, rounded or lobed;
paleas slightly exceeding the lemmas, thin, papery, glabrous, apices usually rounded, rarely acuminate;
anthers 3-6 mm.
straight, sides usually glabrous, sometimes pilose near the base or appressed pubescent, hairs to 0.3 mm;
lower glumes 4-10 mm, acute;
upper glumes 8-14 mm, keels glabrous, lateral veins not present, apices acuminate to obtuse, occasionally apiculate;
lemmas glabrous or sparsely pilose, apices usually acuminate;
paleas slightly exceeding the lemmas, thin, papery, apices obtuse or rounded;
anthers 3-6 mm.
= 60.
= 62.
Spartina foliosa
Spartina alterniflora
Spartina foliosa grows in the intertidal zone from northern California to Baja California, Mexico. Populations in San Francisco Bay are threatened by various introduced species of Spartina. Of particular concern is S. alterniflora, which forms hybrids with S. foliosa that have a broader ecological amplitude than either parent. In California, S. foliosa is often confused with S. densiflora, which is also established in some regions, but S. foliosa differs from that species in being rhizomatous and having softer culms and wider leaf blades.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Spartina alterniflora is found on muddy banks, usually of the intertidal zone, in eastern North and South America, but it is not known from Central America. In addition, it has become established on the west coast of North America, and in England and southeastern France. It hybridizes with S. maritima in Europe, with S. pectinata in Massachusetts, and with S. foliosa in California.
The rhizomes and scales of S. alterniflora have large air spaces, presumably an adaptation to the anaerobic soils of its usual habitat. Decaploid plants tend to be larger than octoploids, but they cannot be reliably distinguished without a chromosome count.
Spartina alterniflora is considered a serious threat to coastal ecosystems in Washington and California. It out-competes many of the native species in these habitats and frequently invades mud flats and channels, converting them to marshlands. Pure S. alterniflora grows within the lower elevational marsh zones in its native range but, in San Francisco Bay, its hybrids with S. foliosa grow both below and above the range of that species.
Spartina alterniflora is now a major weed problem in southeastern China (Normile 2004).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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