Senna bauhinioides, Twinleaf Senna, Southwest Desert Flora

Senna bauhinioides, Twinleaf Senna

Twinleaf Senna has yellow flowers in open clusters on short stalks of 1 to 3; short flowering stalk; the fruit is an oblong pod with soft erect hairs (pubescent) and slight constriction between the internal seeds. Senna bauhinioides

Twinleaf Senna flowers are in open clusters on short stalks as shown here. Most of the plant is covered with soft hairs (tomentose). Senna bauhinioides

Twinleaf Senna has green or grayish-green leaves that are covered with soft hairs (tomentose). The twin oblong leaflets which sets it apart from Coves' Cassia, Senna covesii. Senna bauhinioides

The twin oblong leaflets on Twinleaf Senna set it apart from Coves' Cassia, Senna covesii. Senna bauhinioides

Twinleaf Senna is a low growing up to 4 to 16 inches (10-40 cm) tall or more. The plants prefer dry rocky slopes, sandy areas, low desert grasslands, desert shrublands, mesas chaparral vegetation and woods including pinyon/juniper. Senna bauhinioides

Scientific Name: Senna bauhinioides
Common Name: Twinleaf Senna

Also Called: Shrubby Wild Sensitive-Plant, Twinleaf Senna, Two-leaf Desert Senna (Spanish: daisillo)

Family: Fabaceae or Leguminosae Family

Synonyms: (Cassia bauhinioides, Cassia bauhinioides var. arizonica)

Status: Native

Duration: Perennial

Size: Low growing up to 4 to 16 inches (10-40 cm) or more tall.

Growth Form: Twinleaf Senna is a subshrub or perennial forb/herb; branching; plants with short hairs, (tomentose).

Leaves: Twinleaf Senna has green, grayish-green; covered with soft hairs (tomentose); leaves are compound with twin oblong leaflets.

Flower Color: Twinleaf Senna has yellow flowers in open clusters on short stalks (peduncle) of 1 to 3; the fruit is an oblong pod with soft erect hairs (pubescent); pods with slight constriction between the internal seeds.

Flowering Season: April to August.

Elevation: Approximately 2,000 to 5,500 feet (610 - 1,676 m).

Habitat Preferences: Dry rocky slopes, sandy areas, low desert grasslands, desert shrublands, mesas chaparral vegetation and woods including pinyon/juniper.

Recorded Range: In the United States, Twinleaf Senna is found in Arizona, New Mexico and Texas. In Arizona it occurs in the western and southeastern parts of the state, the south half of New Mexico and western Texas south of New Mexico and mostly east of the Rio Grande River and further south. It is also native to northern and northeast Mexico in Chihuahua, Coahuila, Durango, Sonora and Tamaulipas.

North America & US County Distribution Map for Senna bauhinioides.

North America species range map for Twinleaf Senna, Senna bauhinioides:

North America species range map for Twinleaf Senna, Senna bauhininoides

Click image for full size map.

U.S. Weed Information: Unknown
Invasive/Noxious Weed Information: Unknown
Wetland Indicator: Unknown
Threatened/Endangered Information: Unknown

Genus Information: In North America, USDA Plants Database lists 27 native species and 14 introduced species for Senna. Worldwide, World Flora Online includes 362 accepted species names for the genus. The Plant List lists 351 species for Senna.

The genus Senna was published in 1754 by Philip Miller (1691-1771).

In the Southwestern United States: Arizona has 14 species of genus, California and New Mexico each have 11 species, Nevada has 3 species, Texas has has 23 species and Utah has 0 species. Data approximate, subject to revision.

Several members of the genus Senna have been re-classified from Cassia.

Comments: Twinleaf Senna has twin oblong leaflets which sets it apart from Coves' Cassia, Senna covesii. The type species of Cassia bauhinioides var. arizonica was collected from the Mule Mountains, Cochise County, Arizona.

Twinleaf Cassia and Coves' Cassia generally occupy the same habitat although Coves' Cassia is much more common at lower elevations. Also, Twinleaf Senna will be observed blooming much later in the year, especially following a heavy monsoon.

Also see in Southwest Desert Flora; Coves' Cassia, Senna covesii, Woolly Senna, Senna hirsuta v glaberrima and Baja California Senna, Senna purpusii.

Importance to Wildlife, Birds and Livestock Twinleaf Senna, Senna bauhinioides has attractive flowers, the flowers, their seeds and plants may be visited by hummingbirds and/or small mammals including rodents and granivorous birds in search of food, nectar and protection through cover.

Beneficial Value to Butterflies, Honey Bees and Insects Twinleaf Senna, Senna bauhinioides has attractive flowers, the flowers and their plants may be visited or used by butterflies, moths, flies, honeybees, native bees and other insects in search of nectar, food or shelter and protection.

In addition, according to the Arizona Sonora Desert Museum, "Plant Care Information" notice, Sulphur, Hairstreak and Blue butterflies are attracted to all of the Sennas.

Etymology: The genus “Senna” is from the Arabic name Sana.

The genus Senna was published in 1754 by Philip Miller (1691-1771).

The species epithet “bauhinioides” is in honor of Swiss herbalist and botanist brothers Gaspard Bauhin (1560-1624) and Jean Johannes Bauhin (1541-1613), both of whom were born in Switzerland.

Ethnobotany - Native American Ethnobotany; University of Michigan - Dearborn Unknown.