Fiesta Flower

Fiesta flower (Pholistoma auritum) is a sprawling, branching annual vine that blooms in the spring. The long weak stems grow up through surrounding plants, covering the less exuberant shrubs with tangles of cheerful purple flowers.

The stems and leaves of fiesta flower are covered with hairs that are bent backward, allowing the plant to cling and climb. It is said that Spanish señoritas decorated their party skirts and blouses with sprigs of fiesta flowers, which stuck tightly to the fabric. This gives rise to the flower’s common name.

Description ^3,4,11,23,59

Fiesta flower is a trailing, weak-stemmed annual that uses woody shrubs for support. Stems are square and up to about 5 feet (1.5 m) in length. Stems and leaves are provided with small, stiff, downward-directed prickles that give the plant a grabby, sticky feeling.

Leaves are pinnately divided into 5-9 lobes; lobe margins are smooth. Individual lobes often point toward the base of the leaf. The leaf petioles have broad leafy flaps that wrap around the plant stem.

The showy flowers occur in loose clusters, opening one-at-a-time at the top of a coiled stem that gradually unfurls. Flowers are bisexual and radially symmetrical, broadly cup-shaped, usually less than 1 inch (25 mm) wide. Petals are purple to lavender (rarely blue), paler near the base. In the throat of the flower, five small purple scales surround the base of the stamens, closing the throat and giving the flower a dark eye. Stamens have violet filaments and dark purple anthers which protrude from the flower cup and split longitudinally to release pollen. Sepals have small, leafy appendages that curl outward in the gaps between the unfused sepal tips. Peak bloom is March to May.¹

There are one to four seeds in two-chambered, subspheroid capsules. Sepals enclose the developing capsule. With the curling appendages, the structure looks a bit like a green lantern.

Classification ^2,59

Fiesta flower is a dicot angiosperm in the borage family (Boraginaceae).² Plants in this family often have flowers produced along a coiled stalk (a “scorpioid cyme”). As the stalk unfurls, new flowers open just below the coil while seedpods develop along the older stalk. Plants often have small, stiff hairs. Perhaps the best-known members of the Boraginaceae are borage, which is an annual herb native to Central and Eastern Europe and used in soups and salads, and the garden forget-me-not.⁴¹Other plants in the borage family that are found in the Reserve include common phacelia (Phacelia distans), coast fiddleneck (Amsinkia intermedia) and common cryptantha (Cryptantha intermedia).⁴⁸

Pholistoma is a three species genus previously placed in the waterleaf family (Hydrophyllaceae). Subsequently, the availability of molecular data led to several reinterpretations of these plants including the merging of the waterleaf family into the borage family. This is the system currently used by Jepson,² the authority for this Plant Guide. In 2016, the Boraginales Working Group re-evaluated the borage complex and recommended a separate waterleaf family.⁴²² Many botanists have accepted this revision and Pholistoma is found listed in the Hydrophyllaceae in both the oldest and most recent literature. Research into the relationships between the two families is continuing and the systematics may still be evolving.

All three species of Pholistoma occur in the Reserve; the other two (San Diego fiesta flower, P. racemosum and white fiesta flower, P. membranaceum) have small white flowers. Two varieties of blue fiesta flower are recognized. Ours is P. auritum var. auritum. A second variety (var. arizonicum) is not found in the Reserve and is classified by the California Native Plant Society as rare in California but possibly common elsewhere (2B.3).⁴⁵

Ecology

The small, stiff, downward-directed prickles that cover stems and leaves help fiesta flower cling to and scramble through the surrounding vegetation.⁵⁹

Fiesta flower is reported to be more abundant after a fire.²³

Human Uses

As the common name suggests, young Spanish señoritas are said to have decorated their party gowns with sprays of fiesta flowers, which, because of their peculiar spiny hairs, adhere tightly to fabric.^23,35,174

Interesting Facts

The scientific name, Pholistoma auritum, loosely translates as “scaly mouth with ears”.²¹ Pholis is Greek for scale and stoma for mouth. Together they refer to the dark purple scales that close the throat of the flower; auritum is Latin for eared, a reference to the wing-like ears at the base of the leaf.