Chinese Houses

Collinsia heterophylla

close up of purple flowers
Rios trailhead | March 2011

Chinese houses (Collinsia heterophylla) are showy spring annuals that are indigenous to California. They prefer shady, moist areas within many plant communities. They are especially abundant in the north-facing grassy valley along the Rios trail where they mix with sea dahlias (Leptosyne maritima) and ferns (Polypodium californicum) .

Their common name comes from the spikes of flowers which are arranged in perfect whirls of ever-decreasing diameter, resembling fairy tale Chinese pagodas.

Other Common Names:

purple chinese houses, purple and white chinese houses

Description 2,4,59

Chinese houses are upright, herbaceous annual plants about one foot high with one or a few upright stems. Leaves are bright green, 3/8 – 3 inches (1 – 8 cm). The principal veins are often depressed on the upper surface. The underside of the leaves lack hairs or have only a few hairs on the midveins. The leaf shape is variable, ranging from oblong at the plant base to long-triangular along stem,and decreasing in size upward. The upper leaves lack petioles and clasp the plant stem, pairs forming wing shapes at the stem nodes.

The purple and white flowers are bilaterally symmetrical, about 1/2 across (0.8 – 1.4 cm) . Five petals, united at their bases, form two lips. The upper flares vertically, forming a banner at the top of the flower; the lower lip consists of two lobes forming a horizontal shelf that covers the fifth lobe; this, in turn, is folded longitudinally into a “boat keel” which encloses four stamens and one pistil. In the Reserve, the upper lip is usually white to pale lavender, variously decorated with burgundy-colored dots. The lower petals are deep purple. Flowers of blue, pink, pale lavender and /or the same shade top and bottom have been reported. Most flowers occur in a series of widely-spaced whirls at the top of the stems. The bloom time is March – June.1

Seeds develop in a dry capsule which opens at the top allowing about 20 seeds to shake out.

small purple flowers that extend in different directions

Rios trailhead | March 2014

small flower pods

Developing seed capsules | Rios trailhead | April 2014

close up of leaves that extend in different directions

Paired leaves | Rios trailhead | April 2014

Distribution 7

Chinese houses are endemic to California south of Humboldt County and excluding the Central Valley and eastern desert regions. They are found from nearly sea level to reported maximum altitudes from 2500 feet83 to 6500 feet8 and in a variety of habitat types, from yellow pine forests, to grasslands to chaparral. They prefer shaded slopes that are moist in the spring.

In the Reserve, a colorful display of Chinese houses is found in the spring along the south side of the Central Basin, just west of the eastern end of the Gemma Parks loop trail, at the Sea Dahlia observation site (shown below).

Reserve map of chaparral, coastal sage scrub and grassland

Classification 2,59,84,88

Chinese houses are dicot angiosperms in the plantain family, the Plantaginacea. For many years, they were considered members of the fiqwort family (Scrophulariaceae) but were moved to the plantain family in 1998 on the basis of DNA sequencing. Many available references still present the earlier classification system.

The Plantaginaceae contains nearly 100 genera. Unfortunately for the field botanist, members are morphologically heterogeneous and are not recognized by a few obvious, universal characteristics. The family contains some well-known garden flowers such as snapdragons, foxgloves, and penstemons as well as plantains many of which are obnoxious weeds (not to be confused with the banana of the same name).

The genus, Collinsia, contains approximately 20 species, 17 of which are found in California.7 Species of this genus are characterized by opposite leaves and a folded middle lower petal11 that encloses the reproductive organs. Only one species of Collinsia is found in the Reserve.48

There are two varieties of Chinese houses. Our plants are variety heterophylla, which is the more common and widespread variety.

field of green grass

Rios trailhead | March 2014

purple flowers on a branch

Rios trailhead | March 2011

Tall stems with purple flowers

Photo credit: Barbara Wallach | February 2010

Ecology 82

Chinese houses are pollinated by a variety of wild bees which bring pollen from neighboring plants and promote cross-fertilization. When a pollinator lands on the horizontal lobes of the lower lip, the petals are depressed to expose the reproductive organs in the folded lobe beneath.11

Most flowering plants have mechanisms to discourage self-pollination. This assures a population with variable characteristics so that some individuals may survive (or take advantage of) unexpected environmental situations, encouraging the evolution of genetically superior plants.41 A few plants (peanuts and violas, for instance) are nearly all self-pollinating. This requires less energy to produce seeds because the plant need not produce colorful flowers, nectar or large amounts of pollen with which to attract pollinators.41 This strategy may be advantageous when the population of exterior pollen donors (plants of the same species) or the population of pollinators is small, either of which will reduce the exchange of pollen between plants. These situations might occur at the edge of the population range or in highly variable environments, and then it may be an advantage to the population to forego maintenance of population variability in exchange for population survival.

It is now realized that many plants are adapted to do both – they attract insects for cross-fertilization but also encourage some degree of self-pollination. The genus Collinsia has become a guinea pig (more correctly, guinea plant) for the study of this strategy. When the flower first opens, the non-mature reproductive organs lie near the back of the folded lower lobe. Three of the four stamens sequentially lengthen forward and mature while the pistil is non-receptive; this separation of male and female structures in space and time tends to prevent self-fertilization. However, in Collinsia heterophylla, the style lengthens and matures at the same time as the fourth stamen placing them in close proximity when mature and promoting self-pollination.

close up of fingers holding flower petals open to expose white center

Stamens and pistil enclosed in folded lower lobe | Rios trailhead | April 2014

purple flowers scattered in brush

Rios trailhead | March 2014

small purple flowers that extend in different directions

Rios trailhead | March 2014

Human Uses  

We know of no uses by Native Americans or early settlers. Modern use seems limited to enjoyment as a garden plant.24

Purple and white flowers surrounded by green grass

Photo credit: Barbara Wallach | April 2011

Bundle of purple and white flowers

Photo credit: Barbara Wallach | April 2011

Purple flowers

Rios trailhead | April 2008

Interesting Facts  

Chinese houses are recommended as a plant to attract native pollinators.83 Although few annual plants serve as host plants for butterflies, Chinese houses may serve as a host for the spring azure7 and checkerspot butterflies (W. Butterflies).

The common name comes from the resemblence of the flower spikes to chinese pagodas. Most references attribute the resemblance to the distinct whirls of flowers at the top of the flower spike;23,24,83 one reference59 suggests it is also the similarity between pagoda roof angles and the angle between the upright petal lobes and the lower platform.

two purple petals facing away from each other

Rios trailhead | April 2008

light and dark purple petaled flowers extending in different directions

Rios trailhead | April 2008

light and dark petaled flowers

Rios trailhead | March 2011

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