The California Pitcher Plant Darlingtonia California Torr

BOTANICAL NAME: Darlingtonia californica Torr. Unacceptable synonym: Chrysamphora californica. F amily Sarraceniaceae.

COMMON NAMES: California pitcher plant, cobra plant, cobra lily.

RANGE: Pacific coastal bogs and mountain slopes from Oregon to northern California. Altitude varies from sea level to 2800 m.

DESCRIPTION. — Darlingtonia has mainly erect to sometimes decumbent tubular pitcher leaves which grow up to 90 cm, the semidecumbent leaves tending to be smaller. The pitcher leaves are narrow at the bottom and widen to 12-15 cm in a somewhat globose hood at the top. At the top of the moderate ala is the trap opening, which faces downward and is rather large, measuring up to 3 cm. An apronlike, two-lobed, "fishtail" appendage projects downward from the outside edge of the pitcher opening opposite the ala. From a side view, the whole effect is that of a fancied cobra with expanded hood and a rather large, protruding, forked tongue.

Whereas in the genus Sarracenia the pitcher openings all tend to face the center of the rosette, the pitchers of Darlingtonia twist 180° in either direction as they grow, so that the pitcher openings always face away from the center of the rosette.

The pitchers are mostly pale yellow-green above and a darker green below. In full sunlight, there is frequently much red to yellow coloration of the upper portions of the pitchers. The hood area has numerous confluent light windows, or fenestrations. (See discussion of fenestrations under Sarracenia minor, page 38.) There are nectar glands over much of the upper external surface of the leaf, and these are especially well developed on the tonguelike appendage.

The inner margin of the pitcher opening is rolled into a small collar, and this feature, in addition to numerous downward-pointing hairs lining the hood and depths of the pitcher, discourages the escape of prey.

FLOWERING SEASON: April to August, depending on altitude.

TRAP SEASON: Traps tend to remain over winter if moderately protected.

There is a smooth, hairless zone between the hood and the bottom of the pitcher, however. Darlingtonia has no digestive glands. It is presumed that prey is decomposed by microorganisms and that the nutrients are then absorbed directly by the lining cells. There are no intrinsic enzymes in the pitcher fluid, but the presence of prey, together with certain chemical or mechanical stimulations, does increase the secretion of water from the lining cells into the pitcher cavity.

The plant is perennial, with a long, branching rhizome and fibrous roots. Vegetative reproduction is more prevalent than sexual reproduction. The numerous stolons (runners) which grow from the rhizome are probably most responsible for the massive proliferation of Darlingtonia at suitable locations.

The flower has a tall scape which assumes the form of a shepherd's hook at the time of anthesis (opening). There are several bracts (leafletlike blades) at intervals on the scape. The bracts are colored from pale yellow-green to pink to deep red. The actinomorphic flower has five elongate green sepals, which project horizontally or reflex at their bases, and five pendulous crimson petals, which come to a point and are closely approximated, the result appearing to be a closed, conical corolla. Near the tip of each petal, the lateral borders have semicircular notches, so that, when the petals are seen together, there appear to be five circular openings into the corolla.

Inside the corolla, the large ovary is bell-shaped, and the very short style and five-lobed stellate stigma project down from the flat, wide bottom surface of the bell. The twelve to fifteen short stamens are arranged around the narrower base of the bell. This anatomical structure serves to encourage cross-pollination. A pollinator may enter the flower through the circular openings in the corolla or may separate the tips of the petals. It will likely brush over the stigma at this time

Fig. 4-1. A clump of Darlingtonia. Note the rotation of the pitchers as they have grown, and the large hood.

and deposit pollen collected from other flowers. The pollinator then ascends the bell-shaped ovary to the flower base, where it may collect additional pollen. As it leaves the flower, the sloping configuration of the ovary tends to prevent the pollinator from touching the stigma again, this time with the flower's own pollen. Also, the bell shape prevents pollen from falling directly from the stamens onto the stigma, which is largely shielded under the wide bottom surface of the bell.

The seeds set by autumn. They are pale brown and elongate, up to 2 mm in length. The bulbous end of each seed is covered with numerous short projections, which may indicate dispersion by animals.

GENERAL. — Darlingtonia is quite distinct from the eastern Sarracenia, although if is a member of the same family. Large numbers of these plants growing in great, cool, green, western bogs are equally as attractive as eastern pitcher plants.

The species was discovered in 1841 by J. D. Brack-enridge, a botanist assigned to an exploratory expedition in California. The expedition was constantly threatened with hostile attack, but Brackenridge persisted in wandering from the protection of the main force in order to botanize. He came upon Darlingtonia and had only a few seconds to tear off portions of a few leaves and a seed capsule or two before he had to rush back to the group. Back in the east, the renowned botanist John Torrey immediately realized that the species was new and that it was related to, but different from, Sarracenia. He formally described and named the plant from the scant material hurriedly assembled.

Several years later, a specific search was made for the plant, and it was found in several areas. It was most intensively and lovingly studied by a Mrs. Austin, who grew up in the late nineteenth century in the area of the Feather River in California. As a child, she had guided some of the botanical explorers after Brackenridge to stands of Darlingtonia located in an adjacent valley, which she herself had explored. Although not formally trained, Mrs. Austin spent several decades studying Darlingtonia and submitting detailed notes to the renowned eastern botanist Asa Gray. These notes remain to this day the most complete and exhaustive field study records available on the species. It was Mrs. Austin who determined the nature of the pollination process and the lack of digestive enzymes, which was later confirmed by the entomologist Frank Morton Jones. She even braved a violent mountain thunderstorm to sit among the plants and observe that the hoods do indeed effectively prevent the entry of rainwater into the pitchers.

Darlingtonia grows in sphagnum bogs or in poor peat soils and gravel near springs and cool, fast-running streams. The geologic base rock is serpentine, which has very poor nutrient value. While summer days may become quite warm, the rhizomes and roots are always immersed in boggy slurries that are constantly permeated with cold spring waters which seldom exceed 20°C. The plants occur only rarely in standing-water bogs and seem to do best in —if not require — cool, moving water at the root level. They may thus be seen growing in seepage bogs and springheads, along streams and ponds, and even with minimal foothold in the snags of rapids and waterfalls.

The chief thing that attracts prey seems to be the gland-bearing "fishtail" hood appendage, which is present in modified form even in the earliest seedlings. The appendage attracts not only flying prey to erect pitchers but ground prey to decumbent pitchers as well, when the pitchers are bent and twisted so that the lobe touches the ground. Once, while doing field studies on the species, Frank Morton Jones was carrying an armload of pitchers back to camp when he noticed a butterfly fluttering near and finally landing on the lobe of one of the pitchers, even as he was walking.

Like Sarracenia, Darlingtonia has several insect associates, the most common of which is the larva of a gnat, Metriocnemus edwardsi, which lives in the pitcher liquid but apparently does no harm to the plant.

Fortunately, the California pitcher plant seems destined to be with us for a long while, since at the moment it is not seriously endangered. Many good Dar-

lingtonia areas are parts of state and federal reserves, and the rough, poor land and stunted, deformed trees of mountainous areas discourage agriculture and forestry. The difficulty of access to many of the bogs prevents their being overrun with visitors or easily vandalized. However, even some of our most remote and primitive areas are lately suffering increased use by weekend pioneers, and there is a growing market for the species in the nursery trade.

Fig. 4-2. Art intact flower.

Fig. 4-3. A flower with two petals removed. Note the notching of the remaining petals, the large bell-shaped ovary, and the stamens ringing the base of the ovary.

Fig. 4-4. Close-up of the upper portion of a pitcher. One can clearly see the fishtail appendage, the pitcher opening, and many light windows.

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