Golden Yarrow

Eriophyllum confertiflorum

Overview

Overview

Golden yarrow (Eriophyllum confertiflorum) is native to the coastal sage scrub and chaparral along the west coast of California and northern Baja California. It is a medium, rounded plant that blooms in late spring with clusters of bright yellow flowers

The blossom of golden yarrow is actually a flower within a flower within a flower. What first appears to be a single flower, on closer inspection is seen to consist of several small, daisy-like flowers in a compound flat topped cluster. In turn, each “daisy” consists of two types of flowers. The eye of the “daisy” is formed of tiny symmetrical flowers (disk florets); each “petal” around the edge is a single, asymmetrical flower (a ray floret).

             

  

Description

Description 4,11,23,26,43,59

Golden yarrow is a subshrub usually less than three feet (1 m) high. There is a short tap root, but most of the roots are shallow, within the upper 1.5 feet (40 cm). One to several branching, upright or widely spreading stems form loosely upright to mounding cushions. Stems are covered with white wooly hairs and are reported to be aromatic,4 but we have not noticed an aroma from our plants. Leaves are relatively small, less than two inches (5 cm) long , sessile and deeply pinnately lobed one or two times, with one to three pairs of primary lobes. Leaf margins are rolled under. Leaves are green above, with sparse hairs; leaves below are covered with long, white wooly hairs. Conspicuous axillary buds are swollen, with a white wooly covering.

Flower heads occur in terminal flat-topped or domed compound clusters. Several principal branches end in clusters of 20 or fewer golden flower heads. The involucre is urn-shaped, of one series of ovate or obovate, green phyllaries.  Flower heads are 1/4 to 1/2 inches (0.7-0.9 cm) across, with 4-6 ray florets and 10 or more disk florets. The pappus is greatly reduced. A bilateral ray floret consists of a short tube with one small but conspicuous rounded petal. A ray floret lacks stamens; the pistil has a small, one-chambered inferior ovary, with a single style that extends slightly beyond the tube and has two strongly recurved branches. The symmetrical disk floret is bisexual, with a pistil similar to that of the ray floret. The stamens are united by the bright yellow anthers into a tube around the style. The peak flower time is March-August.1

The one-seeded fruits are elongate, about 1/16 inch (0.18-0.2 cm) long are dark and covered with short straight hairs. The pappus is visible as a few pale, translucent scales at the top of the fruit.  The phyllaries often remain on the plant after the seeds are released, forming  characteristic small dried brown cups.

           
 

Other Common Names: 
Yellow Yarrow, Golden-yarrow

Distribution

Distribution 2,7,89

Golden yarrow is a California native that occurs throughout most of California and south into northern Baja California and northwestern mainland Mexico. Within California it is most concentrated south of San Francisco Bay below 3000 feet (900 m), in the Coast Range and westward, and in the Sierra Nevadas.

Golden yarrow often occurs along trails and road cuts,59 in open areas within chaparral and coastal sage scrub11 and on coastal dunes.59 It is more frequently seen after fires.11,43

In the Reserve, golden yarrow occurs most frequently along the trails on the south side of the Central Basin.

 

This plant occurs primarily in the following vegetation types in the San Elijo Lagoon Ecological Reserve: 
Chaparral
Coastal sage scrub

Classification

Classification

Golden yarrow is a dicot angiosperm in the sunflower family, Asteraceae.2 This is the largest family of vascular plants in the Northern Hemisphere.143 “Flowers” of Asteraceae are made up of one or both of two types of flowers: symmetrical disk florets and strapped-shaped ray florets. These are crowded onto a common base (receptacle) and together are called a flower head.44,49,143 A flower head is often mistaken for a single flower. Other familiar Asteraceae that occur in the Reserve include California sagebrush (Artemisia californica), bush sunflower (Encelia californica), and goldenbush (Isocoma menziesii).48

Species in the genus Eriophyllum are characterized in part by the presence of both ray and disk florets, by a single series of overlapping phyllaries beneath each flower head, by flower heads in more or less flat-topped clusters, and by a pappus that is absent or is reduced to a crown of jagged scales.2

Golden yarrow  is a variable species with two varieties in California. The  variety in the Reserve is var. confertifolium.48

In spite of the common name and flat-topped flower cluster, golden yarrow is not closely related to common yarrow (Achillea millefolium). Both are in the sunflower family, but that is a large family variously subdivided into subfamilies and/or tribes.11,41,143 The two yarrow species belong to different tribes.143

            

Ecology

Ecology

Many plants of the coastal sage scrub respond to fire, not by vegetative resprouting (like many chaparral species) but by means of enhanced seed germination.345 In a recently compiled list,281 golden yarrow was reported to be among the 123 "Species that are always present, but are much more abundant after a fire". Some percentage of the seeds produced by golden yarrow need some stimulus to germinate. Fire and its by-products may be the main stimulus or one of several. In the absence of fire, approximately 25% of the golden yarrow seeds will readily germinate the following year; the rest remain dormant.43 Both charred wood and leachate from ash have shown to be effective in breaking that dormancy. Thus golden yarrow is more abundant in post fire areas, slowly being overgrown as the areas recover. Such species often take refuge between fires in smaller openings, trail edges and disturbances.

Many disparate flowers in the Reserve are more frequent after a fire, often because their germination is stimulated by some component of fire. A of the more familiar are wind poppy (Papaver heterophyllum), California poppy (Eschscholzia californica), rock rose (Crocanthemum scoparium), wild morning glory (Calystegia macrostegia), rattlesnake weed (Daucus pusillus),  yellow pincushion (Chaenactis gabriuscula) and sacapellote (Acourtia microcephala).

           
 

Human Uses

Human Uses

There are relatively few reports of usage by Native Americans. The Kumeyaay boiled the whole plant and used the water as a face wash to treat pimples.16 The Cahuilla, from the inland area of Southern California, ground the parched seeds into flour.282

Today, golden  yarrow is often used in habitat restoration and erosion control.43 It is recommended for native plant gardens, where it is an important nectar source for a variety of insects.24,43,168,290

              

Interesting Facts

Interesting Facts 21

The scientific name of golden yarrow, Eriophyllum confertiflorum, provides more description than many scientific names.
Eryophyllum is derived from the Greek words "erion", meaning wool, and "phyllon", meaning leaf; together they describe the long wooly hairs that cover the stem and lower leaf surfaces. Confertiflorum comes from the Latin "confertus", which means crowded and "flora", meaning flowers which refer to the number of florets on a flower head, and/or the number of flower heads in a cluster.

           

Photos

Central Basin, south side (Rios trailhead); May 2010
Central Basin, south side (Rios trailhead); May 2010
East Basin, south side (Santa Florencia overlook); April 2017
Central Basin, south side (Rios trailhead); May 2010
Central Basin, south side (Rios trailhead); May 2008
Central Basin, south side (Rios trailhead); June 2017
East Basin, south side (Santa Florencia overlook); April 2017
Central Basin, south side (Rios trailhead); May 2017
East Basin, south side (Santa Florencia overlook); April 2017
Central Basin, south side (Rios trailhead); April 2017
Central Basin, south side (Rios trailhead); April 2007
Central Basin, south side (Rios trailhead); April 2010
phyllaries around bases of flower heads; June 2017
ray floret showing recurved branches of style; Central Basin, south side (Rios trailhead); May 2017
disk floret with forked style and tube of old anthers circling below the forks; Central Basin, south side (Rios trailhead); May 2017
seed with scale-like pappus at one end; Central Basin, south side (Rios trailhead); June 2017
Central Basin, south side (Rios trailhead); May 2017
wooly underside of leaf; Central Basin, south side (Rios trailhead); May 2017