Yellow Pincushion

Yellow pincushion (Chaenactis glabriuscula) is a late spring annual that is native only to California and Baja California. It is a variable species with several recognized varieties. Yellow pincushion blooms profusely in early summer, especially in the open areas of East Basin.

Like many of our flowers, yellow pincushion is a composite (a relative of the daisy). What appears to be a single flower is actually a cluster of many florets. Like the eye of a daisy, all the florets of yellow pincushion are disk florets; there are no rays around the outside. The outer disk florets are larger and asymmetrical, flaring outward, giving the flower a distinctive rounded look – like a pincushion. Seeds are long and slim with four flat scales extending at right angles from one end. A ripe seed head resembles a tiny extra-terrestrial communication satellite.

Description ^2,4,23,59

The yellow pincushion is an herbaceous, multi-branched, annual plant that grows 1 – 2 feet high (30 – 60 cm). All parts of the plant may be covered with cobwebby hairs, especially when young, and all parts are glandular and very sticky. One or more slim, green or reddish branching stems arise from a basal rosette of leaves, which is present in the early spring but usually withers soon after flowers start. Large basal leaves may reach 4.5 inches (11 cm) in length. Small, sparse leaves persist along the stems. Leaves are thickened and finely divided once or twice or occasionally undivided; final divisions are often no wider than thick. Leaf surfaces fold up along the central axes, giving them the three-dimensional look of salad greens.

The yellow flowers are composite flower heads consisting only of disk florets of two types that form a hemispherical cluster. The outer florets are larger, even in the buds stage, and asymmetrical, with the larger petals flaring to the outside. These florets are female and have a single pistil with two elongate stigmas curling outward, Inner disk florets are smaller, symmetrical and bisexual. The five stamens are united in a column around the pistil, the “pins” in the “pincushion”. Disk florets open sequentially from the outside. The major bloom time is April through July ¹

The tiny black seeds are slim awl-shapes, less than 1/4 inch long (5 mm). Like many composites (dandelions for example) they are dispersed by means of a pappus at one end that serves as a parachute to carry them in the wind. Unlike many composite flowers, such as dandelions, the parachute does not consist of a tuft of hairs but of four broad, flat scales – little helicopter blades.

Classification  

Yellow pincushion is a dicot angiosperm in the sunflower family, Asteraceae.^2,11 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).

Species in the genus Chaenactis are characterized in part by the lack of ray florets, by the presence of two types of disk florets and by a pappus that consists of four flat scales.

C. glabriuscula is a variable species with five varieties in California. The most common is var. glabriuscula. This is the variety throughout most of the Reserve, and the variety described here. An endangered variety, var. orcuttiana, grows in the dune restoration area of West Basin;⁴⁸ it can be recognized by the ground-hugging growth form and more succulent leaves.

Ecology  

Yellow pincushion is a fire-follower.²⁶ It is not dependent on fire, but either the heat or smoke produced by fire stimulates seed germination,³⁹ and flower production is often much more extensive in burned areas.

Human Uses ⁷⁵

Seeds of yellow pincushion have been described as “strong tasting”. (I could not accumulate enough of the tiny seeds to detect any flavor at all.) The Cahuillas in the Riverside area dried the seeds in the sun, ground them and mixed them with other seeds into a mush.

Interesting Facts  

Yellow pincushion gets its name from its hemispherical shape – like a pincushion – and the straight columns of united stamens that rise above the inner disk florets.²³

NOTE: If you Google “yellow pincushion”, you will find a tropical Protea by that name; it is native to Zimbabwe and South Africa and is used as focal flowers in the florist trade. You can buy 35 stems for $169.