Rare, Threatened and Endangered Plants of Upper Newport Bay

Ron Vanderhoff, Orange County CA Native Plant Society, guest Contributor


Almost everyone reading this article already knows that the Upper Newport Bay is an incredible botanical treasure. Orange County, an area of more than 500,000 acres, has about 1,435 recorded wildland plant species of which about 890 are native. Upper Newport Bay, at only about 1,000 acres, has a flora of 580 species. That is 38% of all the plants of Orange County on about one fifth of one percent of the land mass. Upper Newport Bay is a remarkable place.

Upper Newport Bay has several rare plants as well.  The designation, “Rare,” for a plant is defined as being listed as a CA or US Endangered or Threatened Species or a species listed by the California Native Plant Society Rare Plant Ranking. Of the 18 species at Upper Newport Bay that might fit these criteria, two are suspicious or invalid records, one has had a taxonomic change, one is extinct and six are found in very old records or with uncertain details, bringing the list of the current rarest plants at Upper Newport Bay to a tidy eight species:

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Southern tarplant, Centromadia parryi ssp. australis.
Annual. 2-3ft. Blooms May-Nov. CA Rare Plant Rank 1B.1
A plant of flat, alkaline, silty soils in full sun along the coast. Flat coastal habitat is declining in Southern California; thus, the species is also declining. Interestingly, Southern tarplant requires disturbed soils for its seed germination, thus it is easy to find at many locations where people are, such as right along the edges of Back Bay Drive near the base of Big Canyon. 
The prickly leaves and long summer bloom of small yellow composite flowers are characteristic.
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Salt marsh bird's-beak, Chloropyron maritimum ssp. maritimum
Annual, 6-12in. Blooms May-Sep. U.S. and CA Endangered
Probably the most important plant species at the bay. This somewhat inconspicuous plant lives in the intertidal zone, especially among pickleweeds. It is a hemiparasite on a host plant, forming a root attachment with an appendage called a hausteria. It also photosynthesizes and makes food for itself. This relationship causes little impact to the host, which is often pickleweed, fleshy jaumea or alkali heath.
The colonies at UNB are among the most significant anywhere. The plants growing at UNB are of further interest due to their unique 3-lobed floral calyx (left photo), a character unique from few other colonies to the North or South.
Look for it in summer months in the marsh at the base of Big Canyon or off the entrance road to the Back Bay Science Center.



























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Decumbent goldenbush, Isocoma menziesii var. decumbens
Shrub. 1 x 4ft. Blooms Apr-Nov. CA Rare Plant Rank 1B.2
A low spreading form of our common summer-blooming goldenbush. The variety decumbens is controversial among botanists, who may disagree about its status. Some consider its prostrate growth and hairy foliage to only be a result of its more wind-swept environments, others believe it is genetically and reproductively distinct. 
The common form, I. m. vernonoides is seen throughout sage scrub communities at the bay. This form is exclusive to coastal bluffs.
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Wire grass, Juncus acutus ssp. leopoldii
Perennial. 5ft. Blooms May-Jun. CA Rare Plant Rank 4.2
A distinctive and easily recognized plant. Technically a rush, not a grass. Mature plants look like large rounded masses of straight thin spike-like leaves. The species grows in alkaline and semi-salty environments, sometimes into the upper portion of the marsh but more commonly in the alkali flats slightly above this zone. Look for it along Back Bay drive at many locations.
It is rare due to a decline in suitable habitat throughout its range.
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California boxthorn, Lycium californicum
Shrub. 2x4ft. Blooms Mar-Sep. CA Rare Plant Rank 4.2
A plant strictly of coastal bluff scrub environments, now a limited habitat type in Southern California. This plant colonizes sandy and often steep ocean and bay bluffs, enduring hot dry summers and saline soils and air. Plants are often difficult to access, due to their precarious and usually steep locations.
Boxthorns have small succulent leaves, a common water conserving characteristic of coastal scrub plants. The lateral branches are short and stiff and terminate in a hardened point. Its small white flowers are visited by a number of pollinators.
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Estuary seablite, Suaeda esteroa
Perennial. 2-3ft. Blooms May-Oct. CA Rare Plant Rank 1B.2
Two species of Suaeda are significant at Upper Newport Bay and for many years both were considered the same species. They have since been determined to be unique species. Suaeda esteroa is a plant of the middle to upper portions of the salt marsh, never far from salt water. Like many salt marsh plants (halophytes) it has succulent leaves; smooth in the case of this species.
A member of the same family of plants as our saltbushes (Atriplex) and pickleweeds (Salicornia), which are also masters of salty habitats. Look for it along the edges of the marsh, where its foliage texture distinguishes it from the other marsh plants.


















































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Seablite, Suaeda taxifolia 
Perennial. 2x4ft. Blooms Feb-Nov. CA Rare Plant Rank 4.2
Suaeda taxifolia is our second rare seablite at the bay. Unlike the prior species, this one prefers drier feet and is found on the silty soils and bluffs surrounding the bay.
It also has succulent leaves, but unlike S. esteroa, they are usually slightly hairy.
Often both seablite species may be within sight of one another, but do not overlap, having evolved to exploit different ecological niches.












All Photos: Ron Vanderhoff