Chaparral Yucca

Chaparral yucca (Hesperoyucca whipplei) is a conspicuous native plant of dry rocky slopes in coastal sage scrub and chaparral. It produces a flamboyant cluster of purple-tinged white flowers atop a long stalk, giving rise to imaginative names such as Our Lord’s candle, quixote plant and Spanish bayonet, a name it shares with the other yucca in the area, Mojave yucca (Yucca schidigera). After several years of growth, chaparral yucca blooms once, then dies.

Like other yuccas, Chaparral yucca is dependent upon a small moth for pollination. In turn, the moth is dependent upon the yucca to nourish its larva. Neither the chaparral yucca nor its partner moth can adapt and survive in the absence of the other.

Description ^{4,5,11,59,306}

Chaparral yucca is a perennial that grows 8-10 feet from a dense basal rosette of stiff, strap-shaped, gray-green leaves. The tough, leathery leaves are one to three feet long, fibrous, and tipped with a sharp spine. The margin has tiny but sharp serrations.

Fragrant white or purple-tinged flowers appear between five and eight years of age, in a large, conspicuous cluster at the top of one long, unbranched stalk, several feet long. The flower stalk grows very quickly, four to six inches (10-15 cm) per day.¹⁷⁴ Larger flower clusters contain hundreds of blossoms and may reach four feet (1.5 m) in length. Bisexual flowers are bell-shaped, about 1.5 inches (3.5 cm) across, extended horizontally or pendant from their pedicels. There are three sepals and three petals that are indistinguishable from each other (collectively called tepals). Tepals are mostly cream colored, more or less edged with purple. There are six stamens with very thick, white filaments. Orange pollen is produced in discrete packets, pollinia, two per anther. The single pistil has a superior ovary with a thick style and a green, three-lobed stigma, which is fringed around the edge. Chaparral yucca usually blooms between early March and May.¹

After fertilization, the pedicel reverses and the maturing fruit is erect, a plump green capsule with six shallow longitudinal grooves. The capsule splits open from the tip to expose six columns of seeds, with numerous flattened seeds per column.

Each chaparral yucca flowers only once after which the entire plant dies. Before flowering, a plant may produce smaller plants (“pups”) around the base. Thus the dead stalk of the original plant may leave behind one or more smaller plants, genetically identical to the original.

Classification

Yucca is a perennial monocot in the agave family (Agavaceae). Monocots are an early offshoot of flowering plants, partly characterized by having a single cotyledon (instead of two), by having parallel veins in the leaves (instead of reticulated) and by having flower parts in multiples of three (instead of fours or fives).¹⁷⁶

Members of the agave family are often found in dry habitats.⁷⁶ They have rosettes of stiff, fibrous leaves^11,76 and a fruit with two or more chambers that becomes dry and splits open at maturity.⁴⁴ Many have large, erect, conspicuous flower clusters.⁴¹ The agave family is in a state of flux.^41,306  At present, the authority we follow² retains the agave family as a separate family. Others place it as a subfamily of the asparagus family (Asparagaceae).^41,143 It has also been considered a subfamily under the lily family (Liliaceae).¹¹

Chaparral yucca is one of two yuccas that are found in the Reserve,⁴⁸ both previously combined in the Yucca genus. Both have spectacular clusters of creamy white flowers.  Chaparral yucca can be distinguished from Mojave yucca (Yucca schidigera) by having all leaves in a basal rosette rather than in clusters carried at the end of thick often branching trunks, and also by the absence of long, curly fibers from the leaf edges.²

Ecology ^{41,57,59,483,484,485}

Pollination between different plants is the main mechanism for maintaining genetic diversity and adaptability within a species. In the yuccas, this is promoted by a unique relationship between the plant and a very specialized type of moth. Each of the various species of yucca has its own partner moth. Chaparral yucca is pollinated by Tegeticula maculata whereas our other local yucca, Mojave yucca, is pollinated by T. yuccasella. The Joshua tree (Yucca brevifolia) is pollinated by yet another species of moth.

In all cases the moth is small and nondescript and lacks the long tongue that characterizes most moths and butterflies. Instead, there are tentacles around the mouth that are adapted for gathering pollen. After the female moth is fertilized, she gathers the pollen into a package which she transports to a different plant, often some distance away.⁴⁸⁵ There, she deposits one or a few eggs into the ovary of a fresh flower and packs pollen tightly into the stigma, insuring pollination. She then repeats the process, if necessary gathering more pollen. The moth larvae hatch in about one week and feed on one or a few of the developing seeds. There are generally only a few larvae in any one yucca fruit but several hundred seeds, so both seeds and moth larvae can develop.

At the end of the summer, the moth larvae emerge and drop to the ground where they overwinter, emerging as adults the following year when the bloom and pollination cycles begins again.

Human Uses ¹⁵

“Everything was connected to everything else. Life was whole. Yuccas produced edible flowers as well as a stalk which could be harvested for food or saved for a quiver, and leaves whose natural fiber might be woven into a sandal or twisted into cordage for nets and bows. It is this unbroken image that gave the California Indian such wonderful integrity with the world.” –Paul D. Campbell ⁷⁵

Like the related Mojave yucca (Yucca schidigera), chaparral yucca was – and is – used by many Indian tribes for many purposes, especially for food and for fiber. It seems that, of the two, Mojave yucca was preferred for fiber; fibers were longer and smoother in texture and thus easier to work with. However, chaparral yucca, with its tall, straight flower stem, was preferred for roasting. The base of the plant with leaves removed (called the crown, or head, or cabbage) was a “sort of corn, or staff of life to the people”, usually roasted in a pit of coals or hot rocks, overnight or longer, and allowed to cool. The roasted cabbage has been described as “slightly sweet or like bananas”, and as tasting ” like baked apple”.⁵

Interesting Facts

The name “yucca” was borrowed from the Caribs of South America, who applied the term to the starchy root of a plant in the surge family (Manihot escuelenta), also known as cassava or tapiocca^21,23 Cassava is an important source of dietary carbohydrates in many developing countries.⁴¹ It is unclear why the name “yucca” was applied to our desert plants; perhaps it was a culinary similarity.³²⁷