The Sonoran Desert Florilegium

plants of the florilegium

Calliandra eriophylla with Cottisa gracilis
Fairy duster and Janusia vine


FAMILY:  Malpighiaceae — Malpighia family

SYNONYMS:  Janusia gracilis

OTHER COMMON NAMES:  Slender Janusia

ETYMOLOGY:  The genus Cottsia is an anagram based on the name of Scottish botanist George Francis Scott Elliot (1862–1934).

The species name derives from the Latin gracile, or 'slender'.

GEOGRAPHIC RANGE:  Found from southern AZ to western TX, into northern Mexico

HABITAT:  Dry, rocky slopes and arroyos, 1,000-5,000'

BLOOMING SEASON:  Blooms April to October, depending on rainfall

DESCRIPTION:  Perennial twining vine, 2' tall when unsupported but climbing to 10' when supported by other plants

Flowers are 1–2" in diameter with 20 or more long stamens that extend well beyond the corolla. The sepals and petals are small and inconspicuous when compared to the showy stamens, which are white at the base, darkening to pink and red at the tips.

Dark green leaves are 1" long and covered in fine hairs that give them a silvery cast. Bipinnately compound leaves consiste of 2–4 pairs of pinnae, each with 7–10 leaflets. Leaves are cold and drought deciduous.

Seed pods, 1.25–3.5" long, are flat and brown, covered in a soft white wool with red ridges around the margins of the pod. When pods mature, they split at the margins and curl backwards. These distinctive empty pods remain on the plant for some months.

Mutualistic associations: New World plants in the Malpighia family have oil-producing glands on the undersides of the petals and offer this oil to pollinators instead of nectar. Oil-collecting bees with specialized hind legs scrape up the oil from these glands and return it to their hives where it is mixed with pollen to feed the larvae or used as protective lining for the brood cells.