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alkali weed

Alkali weed

Plant Characteristics : Low, white-hairy perennial herb, usually much branched from base, forming sprawling tufted plants 3-10 in. high; leaves many, oblong or oval, 1/6 to 1/3 in. long, short petioled; fls. on short stalks in the upper lf. axils, petals white; sepals 5; corolla 5-parted, bell shaped and silky hairy; fruit is a small hairy capsule, usually 1-seeded; styles 2; stigma entire, capitate; seed less than 1/8 in. long, broadly ovate, somewhat pointed at the scar end, and pinkish-tan in color, with smooth surface.

Habitat : Especially common in alkali soils, and occurs throughout the Sacramento and San Joaquin Valleys, southward to southern Calif. Below 1200 m. May-Oct.

Name : Greek, Kressa, a Cretan woman. (Munz, Flora So. Calif. 375). Truxillensis probably means from Trujillo, a Spanish place name much used in New Mexico, Venezuela, Peru, Puerto Rico, Honduras and Spain. The type locality given in the original description would indicate, perhaps, which of these places was a source. Certainly not Spain, as this is a native American species. Possibly New Mexico, or American tropic countries. Truxillensis, the x is substituted for the j, which has no counterpoint in Latin. Also x in Spanish has the sound of the Spanish j, as in Oaxaca. (John Johnson).

General : Common in the study area. Photographed at 23rd Street and along Back Bay Dr. between Big Canyon and Eastbluff Dr. I have noted that in the very dry 1987, this plant was more abundant than in previous years. In areas where I had planned to look at Spergularia, I found Cressa in 1987. This is one of the native halophytes listed by Zedler as occurring in the salt marshes of southern Calif. and Baja Calif. She does not list it as occurring in Upper Newport Bay. For a complete list of these halophytes see Spartina foliosa. I have found this plant in the tidal zone and as high as 25 feet above the high tide line. (my comments). Alkali Weed, Cressa truxillensis, is easily overlooked in most southern Calif. marshes. However, its recent increase in abundance at the upper marsh of Los Penasquitos Lagoon and its obvious expansion following disturbance at the Ballona Wetland have stimulated interest in its ecological requirements. Whether it is an indicator of changing conditions or of upper marsh boundaries remains to be seen; but it may prove useful in delimiting areas which could support salt marsh vegetation, provided disturbance were reduced or eliminated. (Zedler 30). A small genus of warm temp. and trop. regions around the world. (Munz, Flora So. Calif. 375).

Text Ref : Hickman, Ed. 521; Munz, Calif Flora 458; Munz, Flora So. Calif. 375; Robbins et al. 345; Roberts 20.

Photo Ref : June 2 83 # 11; April 2 84 # 22; April-May 86 # 21; June-July 93 # 7.

Identity : by R. De Ruff, confirmed by F. Roberts.

Alkali weed Plant Characteristics : Low, white-hairy perennial herb, usually much branched from base, forming sprawling tufted plants 3-10 in. high; leaves many, oblong or oval, 1/6 to 1/3 in.

Alkali Weed

Alkali weed (Cressa truxillensis) is a common but small plant of the upper salt marsh. It may be the most overlooked and understudied component of our flora. The most obvious characteristic is the silver foliage, caused by abundant small hairs that cover leaves and stems. The white flowers are tiny. Young anthers are bright rose-purple, giving the small plant a pop of color but aging brown. The two white styles with ball-shaped stigma, are excreted from the flower like droopy antennae.

Other Common Names:

spreading alkaliweed, alkali plant, alkali clover

Description 2 , 11 , 34 , 59

Alkali weed is an herbaceous, clone-forming perennial generally less than 10 inches (25 cm) high. Tufts of erect to sprawling, mostly unbranched shoots arise from a subsurface rhizone. Shoots are densely covered with small oval, overlapping leaves that stand erect along the stem and are covered with long, silky white hairs that turn the plant gray. Leaves are lanceolate to elliptic, less than 1/2 inch (1.1 cm) long, with smooth margins and with or without short petioles.

Many small flowers are born individually in leaf axils near the ends of the shoots with the younger flowers above, flowers often appearing aligned on one side. The sepals are united at their bases and form short tube that hides the basal portion of the petals. Five white petals are united into a symmetrical funnel-shaped corolla with erect or reflexed lobes that are sometimes tipped with dark rose. The five white stamens have large, arrow-head shaped anthers. Young anthers are often rose purple, giving the flower a pop of color; they age to dark red-brown. The single pistil has a superior ovary with two white styles, each topped with a ball-shaped stigma. Most flowers occur from April – September. 1

The fruit is a small, dry capsule that splits open from the base. Generally only one small, brownish seed is produced per fruit; many fruit are sterile.

Shoots with small, overlapping leaves | Rios trailhead | July 2018

Flowering stems | Rios trailhead | April 2014

Alkali Weed Alkali weed ( Cressa truxillensis ) is a common but small plant of the upper salt marsh. It may be the most overlooked and understudied component of our flora. The most obvious