The inflorescence is a narrow, dense, spike-like stick of branches appressed together, the unit reaching up to 25 centimeters long.

S. alterniflorus was introduced to San Francisco Bay in the 1970s and it quickly began to hybridize with S. foliosus.

Hybrids generally outcompete the native plant and spread rapidly, threatening S. foliosus with localized extirpation.

[5] However, S. foliosus is still the dominant plant at lower tidal elevations in most salt marshes around San Francisco Bay,[6] and numerous locations within the Bay have remained uninfested during ongoing efforts to eradicate S. alterniflorus and hybrids.

Restoration of tidal marsh habitat is in progress at multiple sites, including the planting of cultivated S. foliosus harvested from uninfested locations and propagated in a nursery.