California Bee Plant

“… they are alert little flowers with a gnome-like sort of character that rewards their notice”²³

California bee plant (Scrophularia californica) might have come from a Dr Seuss story. It’s a tall, gangly plant to six feet tall with such tiny red flowers that they are easily overlooked. Bee plant lives up to its name, always busy with the activity of bees – in spite of the fact that bees do not see red.

Bee plant is native to the western United states and adjacent portions of British Columbia and Baja California. It blooms into summer along trails in many parts of the Reserve. In addition to being a favorite of bees, it is a host plant for the variable checkerspot butterfly.

Description ^{4,23,59,261,290}

California bee plant is a tall, branching, somewhat ungainly herbaceous perennial that may reach six feet²³ or more⁴ in height. The stems are square. The bright green leaves are opposite, oval to triangular in shape, up to 7-1/2 inches (19 cm) long; the leaf base is heart-shaped or truncate  and the margins are twice-toothed with coarse irregular teeth, sometimes appearing dissected or lobed. In the Reserve, leaves are hairless and smooth, although they are sometimes reported to have short, sticky glandular hairs below, especially along the veins.^4,59 Leaf petioles are 3-1/2 inches (7 cm) or less and often fused at the base with the petiole of the opposite leaf.

Tiny, dark red flowers occur in compound clusters at the tops of stems. The flower cluster consists of a series of V-shaped nodes, each with a small, green, bract at the base. One branch of the V leads to a single flower, the other branch continues to another fork which again produces one flower and continues the main peduncle. As a consequence of this repeated structure, the peduncles may have a distinct zigzag shape. Although a flower cluster is large, the very open structure and tiny flowers do not produce a striking display, unless one includes the many bees that are in attendance.

Each flower is only about 1/4 inch (0.6 cm) in length. There are five green sepals that remain around the ovary after the petals have dropped. The flower is bisexual and bilaterally symmetrical with two petals up and three down; the latter sometimes appear as two petals to the side and one down. The corolla color is usually a dark red, sometimes faded on the lower portion and often yellowish deep within the throat. There are four fertile stamens, more or less appressed to the lower portion of the throat and extending to the edge of the lower lobes. The fertile anthers are yellow. The fifth stamen is reduced and infertile, mostly fused to the upper throat; the unfused portion is dark red and diamond shape or triangular. There is one pistil with a superior, green two-chambered ovary and a single style with a capitate stigma. The style is appressed to the lower portion of the tube and extends beyond the corolla, bending downward. The pistil matures before the anthers. In this area, the main flowering time is February – July.¹

The fruit is a dry, brownish ovoid capsule that splits open when mature, releasing numerous small, dark seeds.

Classification ^2,59,88

California bee plant is a dicot angiosperm in the figwort family Scrophulariaceae. Historically, the figwort family was a very large family (over 5000 species world-wide) that contained many of our well known local plants, such as snapdragon, monkey flower, Chinese houses and Indian paintbrush. The “scrophs” were typically two-lipped plants with two petals up and three down. However, recent revaluation of the family using modern taxonomic methods has shattered this old family, rearranging morphologically similar species into seven different families.^41,88  The new, reduced figwort family contains only eight species in three genera native in California.² The sole native representative in the flora of the Reserve is California bee plant which remains in the genus Scrophularia. This genus is the only one in the modern figwort family to clearly illustrate the two-lipped bilateral symmetry that characterized the original family.

Within California bee plant, several varieties have been described. None are currently recognized by Jepson.²

Ecology

Bees can not see the color red.⁸⁶ This raises the question of how a plant with only red flowers attracts so many bees – from bumble bees to honey bees to a variety of smaller wasps and bees^4,59,290 – enough bees to give it the common name of bee plant. One simple explanation is that the bees are smelling and being guided by the nectar produced at the base of the flower tube.³⁴⁶ On the other hand, compared with humans, bees’ visual spectrum is shifted to shorter wave lengths – they do not see red but they can see ultra violet. Many plants signal to bees with UV patterns that humans do not see.³⁴⁷ When made apparent to us through specialized photography, these UV signals appear as bulls eyes around the throat of the flower, or as stripes and spots directing the bee toward the pollen and nectar.

Scientists have shown that flowers tend to have a small, negative electric charge. Recent experiments have shown  that bees can sense these electric fields, and even use them to select unfertilized flowers. This may provide another orientation aid to the red-blind bee.³⁴⁸

Human Uses

Native Americans in northern Baja California (La Huerta Diegueno, or Tipai)  made a tea from the root of California bee plant; this was taken to relieve a fever.²¹⁹ The Pomo of northwestern California and the Ohlone of north and central coastal California used it as a poultice or wash for infections and boils.²⁸²

The genus was named in 15th century Italy because some species have rhizomal knobs that resemble scrofula, swollen lymph nodes associated with a type of tuberculosis. Following the thinking of the time, the plant was used as a cure.²³

Interesting Facts

California bee plant is a host for the spiny, black red and yellow larvae of the variable checkerspot butterfly.¹¹⁶ Bee plants contain a type of glycoside that is unpalatable or toxic to vertebrates. This compound is sequestered by the caterpillar, protecting it from birds. The glycoside is carried into the adult stage giving the adult butterfly protection as well.^41,169